diff --git a/TODO.md b/TODO.md
index 4715789..e3c02ef 100644
--- a/TODO.md
+++ b/TODO.md
@@ -52,6 +52,8 @@
 - [x] Fix import modal missing FilePond styling: bundling refactor dropped filepond CSS + file-upload-filepond.js wrapper from admin list page (pre-existing regression)
 - [x] Move 'download empty CSV template' button onto the same line as the Fichier CSV heading (button on the right, styled as btn)
 
+- [x] Rework `parameters.php` admin page: new `Identifiants` section (shared SMTP/PeerTube/Nextcloud username+password) before `Emails`, Emails section without username/password, test-send button moved outside its fieldset, PeerTube merged into one `Paramètres Peertube` fieldset with activation checkbox on top and test button aligned with Enregistrer
+
 ## Enquête: PeerTube auth failed (400) invalid_grant
 - [x] [Diagnosed & reproduced] Single LDAP credential (`xamxam@erg.be`). **Both** mail and PeerTube are now on `portail.erg.school` (LemonLDAP OIDC) SSO — verified: mail.erg.school advertises SMTP `XOAUTH2`/`OAUTHBEARER` after STARTTLS. The difference: mail kept `PLAIN`/`LOGIN` (additive migration) so the app's `PLAIN` auth still works; PeerTube *removed* the `password` grant (hard cutover) so `grant_type=password` → `invalid_grant`. Not fixable with any credential; needs admin to restore password grant, register OIDC client, or (best) set up `authorization_code`+`refresh_token`. Full report in docs/peertube-sso-incident.md.
 - [x] Built `scripts/creds-test.sh` (gum UI) + `scripts/creds-probe.php` (PHP probe) + `just creds-test`, + public `PeerTubeService::probeAuth()` to isolate auth-vs-channel. Probes SMTP AUTH and PeerTube password grant with the stored creds; logs results (never the password). Added `probeAuth` to PeerTubeService.
diff --git a/app/public/assets/css/admin.css b/app/public/assets/css/admin.css
index a392bff..f55eab0 100644
--- a/app/public/assets/css/admin.css
+++ b/app/public/assets/css/admin.css
@@ -1353,6 +1353,22 @@ th.admin-ap-col {
   gap: var(--space-m);
 }
 
+.param-form > .param-form-actions {
+	display: flex;
+	align-items: center;
+	gap: var(--space-s);
+}
+
+/* Spacing between the two fieldsets in the Identifiants section */
+.param-account-fieldset {
+	margin-top: var(--space-l);
+}
+
+/* Remove the top border on the confirm-password row (it follows the new-password row) */
+.param-form > .param-form-row--flush {
+	border-top: none;
+}
+
 .param-form fieldset {
   display: flex;
   flex-direction: column;
@@ -1430,11 +1446,16 @@ th.admin-ap-col {
   gap: var(--space-3xs);
   border-top: 1px solid var(--border-primary);
   padding: var(--space-xs) 0;
+	display: grid;
+	grid-template-columns: 1fr;
+	gap: var(--space-3xs);
+	border-top: 1px solid var(--border-primary);
 }
 
 .param-form > div:first-of-type {
   border-top: none;
   padding-top: 0;
+	border-top: none;
 }
 
 .param-form input[type="password"] {
@@ -1526,6 +1547,10 @@ th.admin-ap-col {
   grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
   gap: var(--space-s);
 }
+.param-grid > .param-checkbox,
+.param-grid > .param-note {
+	grid-column: 1 / -1;
+}
 .param-grid label {
   display: flex;
   flex-direction: column;
diff --git a/app/templates/admin/parametres.php b/app/templates/admin/parametres.php
index c9c7ca2..c5fad0c 100644
--- a/app/templates/admin/parametres.php
+++ b/app/templates/admin/parametres.php
@@ -77,6 +77,146 @@
         </form>
     </section>
 
+    <!-- ══════════════════════════════════════════════════════════════
+         IDENTIFIANTS (common credentials)
+    ══════════════════════════════════════════════════════════════ -->
+    <?php
+    // Inline helpers: emit aria-invalid + error <small> when this field is the culprit.
+    // Shared by the Identifiants and Emails (SMTP) sections below.
+    $smtpFieldErr = function(string $id) use ($smtpErrorField): string {
+        return $smtpErrorField === $id ? ' aria-invalid="true"' : '';
+    };
+    $smtpFieldMsg = function(string $id, string $msg) use ($smtpErrorField): string {
+        return $smtpErrorField === $id
+            ? '<small class="param-field-error" id="' . $id . '-error">' . htmlspecialchars($msg) . '</small>'
+            : '';
+    };
+    // Human-readable hints per field (brief — the full message is in the toast)
+    $smtpHints = [
+        'smtp_host'       => 'Vérifiez l’adresse du serveur SMTP.',
+        'smtp_port'       => 'Vérifiez le numéro de port.',
+        'smtp_encryption' => 'Vérifiez le mode de chiffrement.',
+        'smtp_username'   => 'Vérifiez le nom d’utilisateur.',
+        'smtp_password'   => 'Mot de passe incorrect.',
+    ];
+    ?>
+    <section aria-labelledby="settings-identifiants-title">
+        <h2 id="settings-identifiants-title">Identifiants</h2>
+        <p>
+            Identifiants communs partagés par le relay SMTP, la connexion
+            PeerTube et l'instance Nextcloud utilisés par le script de sauvegarde.
+        </p>
+        <form method="post" action="actions/settings.php" class="param-form"
+              <?= $smtpErrorField ? 'data-smtp-error-field="' . htmlspecialchars($smtpErrorField) . '"' : '' ?>>
+            <input type="hidden" name="csrf_token" value="<?= htmlspecialchars($_SESSION['csrf_token']) ?>">
+            <input type="hidden" name="section" value="smtp">
+
+            <fieldset class="param-grid">
+                <legend>Identifiants communs</legend>
+                <div>
+                    <label for="smtp_username">Adresse e-mail</label>
+                    <input type="email" id="smtp_username" name="smtp_username"
+                           value="<?= htmlspecialchars($smtpSettings['username']) ?>"
+                           placeholder="xamxam@erg.be"
+                           <?= $smtpFieldErr('smtp_username') ?>
+                           <?= $smtpErrorField === 'smtp_username' ? 'aria-describedby="smtp_username-error"' : '' ?>>
+                    <small>Utilisée pour l'authentification SMTP, PeerTube et Nextcloud.</small>
+                    <?= $smtpFieldMsg('smtp_username', $smtpHints['smtp_username']) ?>
+                </div>
+
+                <div>
+                    <label for="smtp_password">Mot de passe</label>
+                    <input type="password" id="smtp_password" name="smtp_password"
+                           value=""
+                           autocomplete="new-password"
+                           placeholder="Laissez vide pour ne pas modifier"
+                           <?= $smtpFieldErr('smtp_password') ?>
+                           <?= $smtpErrorField === 'smtp_password' ? 'aria-describedby="smtp_password-error"' : '' ?>>
+                    <?= $smtpFieldMsg('smtp_password', $smtpHints['smtp_password']) ?>
+                </div>
+            </fieldset>
+
+            <button type="submit" class="btn btn--primary">Enregistrer</button>
+        </form>
+
+        <fieldset class="param-account-fieldset">
+            <legend>Compte administrateur</legend>
+
+            <dl class="param-account-status">
+                <div>
+                    <dt>Authentification PHP</dt>
+                    <dd><?php $badgeType = 'ok'; $badgeValue = $hasPassword; $badgeOkLabel = 'Active'; $badgeWarnLabel = 'Non configurée'; include APP_ROOT . '/templates/partials/status-badge.php'; ?></dd>
+                </div>
+                <div>
+                    <dt>Stockage du hash</dt>
+                    <dd>
+                        <code>site_settings (DB)</code>
+                        <?php $badgeType = 'ok'; $badgeValue = $hasPassword; $badgeOkLabel = 'Présent'; $badgeWarnLabel = 'Absent'; include APP_ROOT . '/templates/partials/status-badge.php'; ?>
+                    </dd>
+                </div>
+            </dl>
+
+            <?php if (!$hasPassword): ?>
+            <p class="param-note">
+                Aucun mot de passe PHP configuré. Le formulaire ci-dessous stockera
+                un hash bcrypt dans la base de données.
+            </p>
+            <?php endif; ?>
+
+            <form method="post" action="/admin/actions/account.php" class="param-form" autocomplete="off" id="account-password-form">
+                <input type="hidden" name="csrf_token" value="<?= htmlspecialchars($_SESSION['csrf_token']) ?>">
+                <input type="hidden" name="redirect" value="/admin/parametres.php">
+
+                <?php if ($hasPassword): ?>
+                <div>
+                    <label for="current_password">Mot de passe actuel</label>
+                    <input type="password" id="current_password"
+                           name="current_password" required autocomplete="current-password">
+                </div>
+                <?php endif; ?>
+
+                <div>
+                    <label for="new_password">Nouveau mot de passe</label>
+                    <input type="password" id="new_password"
+                           name="new_password" required autocomplete="new-password"
+                           minlength="12">
+                    <small>Minimum 12 caractères.</small>
+                </div>
+
+                <div class="param-form-row--flush">
+                    <label for="confirm_password">Confirmer le mot de passe</label>
+                    <input type="password" id="confirm_password"
+                           name="confirm_password" required autocomplete="new-password">
+                </div>
+            </form>
+
+            <!-- Danger zone: remove credentials -->
+            <?php if ($hasPassword): ?>
+            <fieldset class="param-danger-zone">
+                <legend>Supprimer la configuration du mot de passe</legend>
+                <p>
+                    Supprime le hash de la base de données. L'accès admin
+                    ne sera plus protégé (mode développement).
+                </p>
+                <?php /* TODO: replace this browser confirm() with a proper <dialog> modal like the other confirmations */ ?>
+                <form method="post" action="/admin/actions/account.php"
+                      onsubmit="return confirm('Supprimer le mot de passe ? L\'accès admin ne sera plus protégé.')">
+                    <input type="hidden" name="csrf_token" value="<?= htmlspecialchars($_SESSION['csrf_token']) ?>">
+                    <input type="hidden" name="action" value="remove_credentials">
+                    <input type="hidden" name="redirect" value="/admin/parametres.php">
+                    <input type="hidden" name="current_password_remove" value="">
+                    <button type="submit" class="btn btn--danger">Supprimer le mot de passe</button>
+                </form>
+            </fieldset>
+            <?php endif; ?>
+
+        </fieldset>
+
+        <button type="submit" class="btn btn--primary" form="account-password-form">
+            Mettre à jour le mot de passe
+        </button>
+    </section>
+
     <!-- ══════════════════════════════════════════════════════════════
          RELAY SMTP
     ══════════════════════════════════════════════════════════════ -->
@@ -95,25 +235,6 @@
             <?php endif; ?>
         </div>
 
-        <?php
-        // Inline helper: emit aria-invalid + error <small> when this field is the culprit
-        $smtpFieldErr = function(string $id) use ($smtpErrorField): string {
-            return $smtpErrorField === $id ? ' aria-invalid="true"' : '';
-        };
-        $smtpFieldMsg = function(string $id, string $msg) use ($smtpErrorField): string {
-            return $smtpErrorField === $id
-                ? '<small class="param-field-error" id="' . $id . '-error">' . htmlspecialchars($msg) . '</small>'
-                : '';
-        };
-        // Human-readable hints per field (brief — the full message is in the toast)
-        $smtpHints = [
-            'smtp_host'       => 'Vérifiez l’adresse du serveur SMTP.',
-            'smtp_port'       => 'Vérifiez le numéro de port.',
-            'smtp_encryption' => 'Vérifiez le mode de chiffrement.',
-            'smtp_username'   => 'Vérifiez le nom d’utilisateur.',
-            'smtp_password'   => 'Mot de passe incorrect.',
-        ];
-        ?>
         <form method="post" action="actions/settings.php" class="param-form"
               <?= $smtpErrorField ? 'data-smtp-error-field="' . htmlspecialchars($smtpErrorField) . '"' : '' ?>>
             <input type="hidden" name="csrf_token" value="<?= htmlspecialchars($_SESSION['csrf_token']) ?>">
@@ -154,28 +275,6 @@
                     <?= $smtpFieldMsg('smtp_encryption', $smtpHints['smtp_encryption']) ?>
                 </div>
 
-                <div>
-                    <label for="smtp_username">Adresse e-mail</label>
-                    <input type="email" id="smtp_username" name="smtp_username"
-                           value="<?= htmlspecialchars($smtpSettings['username']) ?>"
-                           placeholder="xamxam@erg.be"
-                           <?= $smtpFieldErr('smtp_username') ?>
-                           <?= $smtpErrorField === 'smtp_username' ? 'aria-describedby="smtp_username-error"' : '' ?>>
-                    <small>Adresse utilisée pour l'authentification SMTP et comme expéditeur.</small>
-                    <?= $smtpFieldMsg('smtp_username', $smtpHints['smtp_username']) ?>
-                </div>
-
-                <div>
-                    <label for="smtp_password">Mot de passe</label>
-                    <input type="password" id="smtp_password" name="smtp_password"
-                           value=""
-                           autocomplete="new-password"
-                           placeholder="Laissez vide pour ne pas modifier"
-                           <?= $smtpFieldErr('smtp_password') ?>
-                           <?= $smtpErrorField === 'smtp_password' ? 'aria-describedby="smtp_password-error"' : '' ?>>
-                    <?= $smtpFieldMsg('smtp_password', $smtpHints['smtp_password']) ?>
-                </div>
-
                 <div>
                     <label for="smtp_from_name">Nom d'expéditeur</label>
                     <input type="text" id="smtp_from_name" name="smtp_from_name"
@@ -195,25 +294,27 @@
         </form>
 
         <!-- Test d'envoi -->
-        <fieldset class="param-smtp-test">
-            <legend>Tester l'envoi d'un e-mail</legend>
-            <p>Envoie un e-mail de test via le relay SMTP configuré ci-dessus.</p>
-            <?php if (!$smtpConfigured): ?>
-                <p class="param-note">⚠ Configurez le relay SMTP avant de pouvoir tester l'envoi.</p>
-            <?php else: ?>
-                <form method="post" action="actions/smtp-test.php" class="param-form">
-                    <input type="hidden" name="csrf_token" value="<?= htmlspecialchars($_SESSION['csrf_token']) ?>">
+        <form method="post" action="actions/smtp-test.php" class="param-form param-smtp-test">
+            <input type="hidden" name="csrf_token" value="<?= htmlspecialchars($_SESSION['csrf_token']) ?>">
+            <fieldset>
+                <legend>Tester l'envoi d'un e-mail</legend>
+                <p>Envoie un e-mail de test via le relay SMTP configuré ci-dessus.</p>
+                <?php if (!$smtpConfigured): ?>
+                    <p class="param-note">⚠ Configurez le relay SMTP avant de pouvoir tester l'envoi.</p>
+                <?php else: ?>
                     <div class="param-smtp-test-row">
                         <div>
                             <label for="smtp_test_email">Adresse de destination</label>
                             <input type="email" id="smtp_test_email" name="test_email"
                                    placeholder="test@example.com" required>
                         </div>
-                        <button type="submit" class="btn btn--primary">Envoyer le test</button>
                     </div>
-                </form>
+                <?php endif; ?>
+            </fieldset>
+            <?php if ($smtpConfigured): ?>
+                <button type="submit" class="btn btn--primary">Envoyer le test</button>
             <?php endif; ?>
-        </fieldset>
+        </form>
     </section>
 
     <!-- ══════════════════════════════════════════════════════════════
@@ -239,8 +340,8 @@
             <input type="hidden" name="csrf_token" value="<?= htmlspecialchars($_SESSION['csrf_token']) ?>">
             <input type="hidden" name="section" value="peertube">
 
-            <fieldset>
-                <legend>Activation</legend>
+            <fieldset class="param-grid">
+                <legend>Paramètres Peertube</legend>
                 <label class="param-checkbox">
                     <input type="checkbox" name="peertube_upload_enabled" value="1"
                            <?= $peerTubeEnabled ? 'checked' : '' ?>>
@@ -250,15 +351,10 @@
                         sur l'instance PeerTube plutôt que stockés localement sur le serveur.</small>
                     </span>
                 </label>
-            </fieldset>
 
-
-            <fieldset class="param-grid">
-            <legend>Paramètres Peertube</legend>
-            <p class="param-note">
-                ℹ L'authentification PeerTube utilise les mêmes identifiants que le
-                <strong>relay SMTP</strong> configuré ci-dessus.
-            </p>
+                <p class="param-note">
+                    ℹ L'authentification PeerTube utilise les identifiants communs configurés ci-dessus.
+                </p>
 
                 <div>
                     <label for="peertube_instance_url">URL de l'instance PeerTube</label>
@@ -286,98 +382,21 @@
                 </div>
             </fieldset>
 
-            <button type="submit" class="btn btn--primary">Enregistrer</button>
-            <button type="button" class="btn btn--secondary" id="peertube-test-btn"
-                    hx-post="/admin/actions/peertube-test.php"
-                    hx-target="#peertube-test-result"
-                    hx-include="closest form"
-                    hx-indicator="#peertube-test-spinner">
-                Tester la connexion
-            </button>
-            <span id="peertube-test-spinner" class="htmx-indicator" style="display:none;margin-left:var(--space-xs);">⏳</span>
+            <div class="param-form-actions">
+                <button type="submit" class="btn btn--primary">Enregistrer</button>
+                <button type="button" class="btn btn--secondary" id="peertube-test-btn"
+                        hx-post="/admin/actions/peertube-test.php"
+                        hx-target="#peertube-test-result"
+                        hx-include="closest form"
+                        hx-indicator="#peertube-test-spinner">
+                    Tester la connexion
+                </button>
+                <span id="peertube-test-spinner" class="htmx-indicator" style="display:none;">⏳</span>
+            </div>
             <div id="peertube-test-result" style="margin-top:var(--space-xs);"></div>
         </form>
     </section>
 
-    <!-- ══════════════════════════════════════════════════════════════
-         COMPTE ADMINISTRATEUR
-    ══════════════════════════════════════════════════════════════ -->
-    <section aria-labelledby="settings-account-title">
-        <h2 id="settings-account-title">Compte administrateur</h2>
-
-        <dl class="param-account-status">
-            <div>
-                <dt>Authentification PHP</dt>
-                <dd><?php $badgeType = 'ok'; $badgeValue = $hasPassword; $badgeOkLabel = 'Active'; $badgeWarnLabel = 'Non configurée'; include APP_ROOT . '/templates/partials/status-badge.php'; ?></dd>
-            </div>
-            <div>
-                <dt>Stockage du hash</dt>
-                <dd>
-                    <code>site_settings (DB)</code>
-                    <?php $badgeType = 'ok'; $badgeValue = $hasPassword; $badgeOkLabel = 'Présent'; $badgeWarnLabel = 'Absent'; include APP_ROOT . '/templates/partials/status-badge.php'; ?>
-                </dd>
-            </div>
-        </dl>
-
-        <?php if (!$hasPassword): ?>
-        <p class="param-note">
-            Aucun mot de passe PHP configuré. Le formulaire ci-dessous stockera
-            un hash bcrypt dans la base de données.
-        </p>
-        <?php endif; ?>
-
-        <form method="post" action="/admin/actions/account.php" class="param-form" autocomplete="off">
-            <input type="hidden" name="csrf_token" value="<?= htmlspecialchars($_SESSION['csrf_token']) ?>">
-            <input type="hidden" name="redirect" value="/admin/parametres.php">
-
-            <?php if ($hasPassword): ?>
-            <div>
-                <label for="current_password">Mot de passe actuel</label>
-                <input type="password" id="current_password"
-                       name="current_password" required autocomplete="current-password">
-            </div>
-            <?php endif; ?>
-
-            <div>
-                <label for="new_password">Nouveau mot de passe</label>
-                <input type="password" id="new_password"
-                       name="new_password" required autocomplete="new-password"
-                       minlength="12">
-                <small>Minimum 12 caractères.</small>
-            </div>
-
-            <div>
-                <label for="confirm_password">Confirmer le mot de passe</label>
-                <input type="password" id="confirm_password"
-                       name="confirm_password" required autocomplete="new-password">
-            </div>
-
-            <button type="submit" class="btn btn--primary">
-                <?= $hasPassword ? 'Mettre à jour le mot de passe' : 'Définir le mot de passe' ?>
-            </button>
-        </form>
-
-        <!-- Danger zone: remove credentials -->
-        <?php if ($hasPassword): ?>
-        <fieldset class="param-danger-zone">
-            <legend>Supprimer la configuration du mot de passe</legend>
-            <p>
-                Supprime le hash de la base de données. L'accès admin
-                ne sera plus protégé (mode développement).
-            </p>
-            <?php /* TODO: replace this browser confirm() with a proper <dialog> modal like the other confirmations */ ?>
-            <form method="post" action="/admin/actions/account.php"
-                  onsubmit="return confirm('Supprimer le mot de passe ? L\'accès admin ne sera plus protégé.')">
-                <input type="hidden" name="csrf_token" value="<?= htmlspecialchars($_SESSION['csrf_token']) ?>">
-                <input type="hidden" name="action" value="remove_credentials">
-                <input type="hidden" name="redirect" value="/admin/parametres.php">
-                <input type="hidden" name="current_password_remove" value="">
-                <button type="submit" class="btn btn--danger">Supprimer le mot de passe</button>
-            </form>
-        </fieldset>
-        <?php endif; ?>
-    </section>
-
     <!-- ══════════════════════════════════════════════════════════════
          SYSTÈME
     ══════════════════════════════════════════════════════════════ -->