diff --git a/TODO.md b/TODO.md
index 698d78f..a62136c 100644
--- a/TODO.md
+++ b/TODO.md
@@ -1,5 +1,13 @@
 # Current tasks
 
+## Mots-clés fieldset in contenus
+- [x] Create contenus-motscles-fragment.php (tags fragment mirroring langues)
+- [x] Add Mots-clés fieldset to contenus template (search + table + bulk actions)
+- [x] Keep button linking to dedicated tags.php page as backup
+- [x] Add "Annuler" cancel button to both langues and mots-clés bulk action bars
+- [x] Add max-height:50vh + overflow-y:auto to both table wraps
+- [ ] Deploy: just deploy
+
 ## Tmp file cleanup (stale filepond + _trash)
 - [x] Session-based detection: check manifest session_id against PHP session files
 - [x] DB-based detection for _trash: check thesis_files row still exists
@@ -10,6 +18,15 @@
 - [x] .gitignore: exclude tmp/filepond/* and tmp/_trash/*
 - [ ] Deploy: just deploy
 
+## Index page improvements
+- [x] Remove 'Mots-clés' button from toolbar
+- [x] Move export to bulk selection bar (Exporter CSV + Exporter fichiers buttons)
+- [x] Export dispatcher accepts ?ids= for per-selection filtering
+- [x] All ExportController/Database export methods accept optional thesisIds
+- [x] Graceful error when ZipArchive extension missing (php8.4-zip not installed)
+- [x] Move DB export (SQLite download) to paramètres → Maintenance section
+- [x] Sticky thead on index table (position: sticky, top: 0, z-index: 5)
+
 ## Dialog & trash page margins
 - [x] Add admin-dialog__body CSS rule with padding + margin resets
 - [x] Add admin-dialog__stats + admin-dialog__hint classes
diff --git a/app/public/admin/contenus-langues-fragment.php b/app/public/admin/contenus-langues-fragment.php
index b97f107..becad46 100644
--- a/app/public/admin/contenus-langues-fragment.php
+++ b/app/public/admin/contenus-langues-fragment.php
@@ -27,6 +27,10 @@ try {
 <div id="langues-bulk-actions" class="admin-bulk-actions" style="display:none">
     <strong><span id="langues-selected-count">0</span> langue(s) sélectionnée(s)</strong>
     <div class="admin-bulk-btns">
+        <button type="button" class="btn btn--sm btn--secondary" onclick="languesCancelSelection()" title="Annuler la sélection">
+            <svg xmlns="http://www.w3.org/2000/svg" width="32" height="32" fill="currentColor" viewBox="0 0 256 256"><path d="M208.49,191.51a12,12,0,0,1-17,17L128,145,64.49,208.49a12,12,0,0,1-17-17L111,128,47.51,64.49a12,12,0,0,1,17-17L128,111l63.51-63.52a12,12,0,0,1,17,17L145,128Z"/></svg>
+            Annuler
+        </button>
         <button type="button" class="btn btn--sm btn--warning admin-btn-merge"
                 onclick="languesConfirmBulkMerge()"
                 title="Fusionner les langues sélectionnées">
diff --git a/app/public/admin/contenus-motscles-fragment.php b/app/public/admin/contenus-motscles-fragment.php
new file mode 100644
index 0000000..d807032
--- /dev/null
+++ b/app/public/admin/contenus-motscles-fragment.php
@@ -0,0 +1,93 @@
+<?php
+/**
+ * contenus-motscles-fragment.php
+ *
+ * HTMX fragment: returns the mots-clés table for the contenus page,
+ * optionally filtered by a search query.
+ */
+require_once __DIR__ . '/../../bootstrap.php';
+require_once __DIR__ . '/../../src/AdminAuth.php';
+AdminAuth::requireLogin();
+
+if (empty($_SESSION['csrf_token'])) {
+    $_SESSION['csrf_token'] = bin2hex(random_bytes(32));
+}
+
+require_once __DIR__ . '/../../src/Database.php';
+
+$searchQuery = trim($_GET['q'] ?? '');
+
+try {
+    $db   = new Database();
+    $tags = ($searchQuery !== '') ? $db->searchTags($searchQuery) : $db->getAllTagsWithCount();
+} catch (Exception $e) {
+    die('<div class="flash-error">Erreur : ' . htmlspecialchars($e->getMessage()) . '</div>');
+}
+?>
+<div id="motscles-bulk-actions" class="admin-bulk-actions" style="display:none">
+    <strong><span id="motscles-selected-count">0</span> mot(s)-clé(s) sélectionné(s)</strong>
+    <div class="admin-bulk-btns">
+        <button type="button" class="btn btn--sm btn--secondary" onclick="motsclesCancelSelection()" title="Annuler la sélection">
+            <svg xmlns="http://www.w3.org/2000/svg" width="32" height="32" fill="currentColor" viewBox="0 0 256 256"><path d="M208.49,191.51a12,12,0,0,1-17,17L128,145,64.49,208.49a12,12,0,0,1-17-17L111,128,47.51,64.49a12,12,0,0,1,17-17L128,111l63.51-63.52a12,12,0,0,1,17,17L145,128Z"/></svg>
+            Annuler
+        </button>
+        <button type="button" class="btn btn--sm btn--warning admin-btn-merge"
+                onclick="motsclesConfirmBulkMerge()"
+                title="Fusionner les mots-clés sélectionnés">
+            <svg xmlns="http://www.w3.org/2000/svg" width="32" height="32" fill="currentColor" viewBox="0 0 256 256"><path d="M224,152V96a8,8,0,0,0-8-8H168V40a8,8,0,0,0-8-8H40a8,8,0,0,0-8,8v64h0v56a8,8,0,0,0,8,8H88v48a8,8,0,0,0,8,8H216a8,8,0,0,0,8-8V152Zm-68.69,56L48,100.69V59.31L196.69,208Zm-96-160h41.38L208,155.31v41.38ZM208,132.69,179.31,104H208Zm-56-56L123.31,48H152ZM48,123.31,76.69,152H48Zm56,56L132.69,208H104Z"></path></svg>
+            Fusionner
+        </button>
+    </div>
+</div>
+
+<form id="motscles-bulk-form" method="post" action="actions/tag.php">
+    <input type="hidden" name="csrf_token" value="<?= htmlspecialchars($_SESSION['csrf_token']) ?>">
+    <input type="hidden" name="action" value="merge_bulk">
+    <input type="hidden" name="return" value="/admin/contenus.php">
+    <input type="hidden" name="target_id" id="motscles-bulk-target" value="">
+    <div id="motscles-bulk-checkboxes"></div>
+</form>
+
+<table>
+    <thead>
+        <tr>
+            <th scope="col" style="width:1%"><input type="checkbox" onchange="motsclesToggleAll(this)"></th>
+            <th scope="col">Nom</th>
+            <th scope="col" style="width:1%;white-space:nowrap">TFE Associé</th>
+            <th scope="col" style="width:1%">Actions</th>
+        </tr>
+    </thead>
+    <tbody>
+        <?php if (empty($tags)): ?>
+        <tr><td colspan="4" class="admin-empty">Aucun mot-clé trouvé.</td></tr>
+        <?php else: ?>
+        <?php foreach ($tags as $tag): ?>
+        <tr>
+            <td style="width:1%"><input type="checkbox" name="selected_tags[]" value="<?= (int)$tag['id'] ?>" onchange="motsclesUpdateBulk()"></td>
+            <td id="motscles-name-<?= (int)$tag['id'] ?>" data-name="<?= htmlspecialchars($tag['name']) ?>">
+                <span class="tag-name-cell"><?= htmlspecialchars($tag['name']) ?></span>
+                <button type="button" class="admin-icon-btn admin-icon-btn--edit" title="Renommer"
+                        onclick="motsclesStartRename(<?= (int)$tag['id'] ?>)">
+                    <svg xmlns="http://www.w3.org/2000/svg" width="32" height="32" fill="currentColor" viewBox="0 0 256 256"><path d="M248,92.68a15.86,15.86,0,0,0-4.69-11.31L174.63,12.68a16,16,0,0,0-22.63,0L123.57,41.11l-58,21.77A16.06,16.06,0,0,0,55.35,75.23L32.11,214.68A8,8,0,0,0,40,224a8.4,8.4,0,0,0,1.32-.11l139.44-23.24a16,16,0,0,0,12.35-10.17l21.77-58L243.31,104A15.87,15.87,0,0,0,248,92.68Zm-69.87,92.19L63.32,204l47.37-47.37a28,28,0,1,0-11.32-11.32L52,192.7,71.13,77.86,126,57.29,198.7,130ZM112,132a12,12,0,1,1,12,12A12,12,0,0,1,112,132Zm96-15.32L139.31,48l24-24L232,92.68Z"></path></svg>
+                </button>
+            </td>
+            <td class="admin-tags-count" style="width:1%;white-space:nowrap"><?= (int)$tag['thesis_count'] ?></td>
+            <td class="admin-actions-col" style="width:1%">
+                <div class="admin-actions">
+                    <form method="post" action="actions/tag.php" class="admin-inline-form">
+                        <input type="hidden" name="csrf_token" value="<?= htmlspecialchars($_SESSION['csrf_token']) ?>">
+                        <input type="hidden" name="action" value="delete">
+                        <input type="hidden" name="return" value="/admin/contenus.php">
+                        <input type="hidden" name="tag_id" value="<?= (int)$tag['id'] ?>">
+                        <button type="button" class="admin-icon-btn admin-icon-btn--delete" title="Supprimer"
+                                onclick="motsclesConfirmDelete(this, <?= htmlspecialchars(json_encode($tag['name']), ENT_QUOTES) ?>)">
+                            <svg xmlns="http://www.w3.org/2000/svg" width="32" height="32" fill="currentColor" viewBox="0 0 256 256"><path d="M216,48H176V40a24,24,0,0,0-24-24H104A24,24,0,0,0,80,40v8H40a8,8,0,0,0,0,16h8V208a16,16,0,0,0,16,16H192a16,16,0,0,0,16-16V64h8a8,8,0,0,0,0-16ZM96,40a8,8,0,0,1,8-8h48a8,8,0,0,1,8,8v8H96Zm96,168H64V64H192ZM112,104v64a8,8,0,0,1-16,0V104a8,8,0,0,1,16,0Zm48,0v64a8,8,0,0,1-16,0V104a8,8,0,0,1,16,0Z"></path></svg>
+                        </button>
+                    </form>
+                </div>
+            </td>
+        </tr>
+        <?php endforeach; ?>
+        <?php endif; ?>
+    </tbody>
+</table>
diff --git a/app/storage/logs/admin.log b/app/storage/logs/admin.log
index eae5b6d..db5b7f2 100644
--- a/app/storage/logs/admin.log
+++ b/app/storage/logs/admin.log
@@ -364,3 +364,4 @@
 {"timestamp":"2026-05-18T15:20:07+00:00","ip":"127.0.0.1","user_agent":"Mozilla/5.0 (X11; Linux x86_64; rv:150.0) Gecko/20100101 Firefox/150.0","resource":"thesis","action":"edit","status":"success","context":{"thesis_id":1263,"title":"Pourquoi les artistes sont-ils encore sur Instagram alors que j’ai vu une story disant qu’il fallait quitter META"}}
 {"timestamp":"2026-05-19T14:39:37+00:00","ip":"127.0.0.1","user_agent":"Mozilla/5.0 (X11; Linux x86_64; rv:150.0) Gecko/20100101 Firefox/150.0","resource":"share_link","action":"deactivate","status":"success","context":{"link_id":213}}
 {"timestamp":"2026-05-19T14:39:39+00:00","ip":"127.0.0.1","user_agent":"Mozilla/5.0 (X11; Linux x86_64; rv:150.0) Gecko/20100101 Firefox/150.0","resource":"share_link","action":"activate","status":"success","context":{"link_id":213}}
+{"timestamp":"2026-05-19T17:19:51+00:00","ip":"127.0.0.1","user_agent":"Mozilla/5.0 (X11; Linux x86_64; rv:150.0) Gecko/20100101 Firefox/150.0","resource":"system","action":"files_export","status":"success","context":{"file_count":6,"byte_size":11871654}}
diff --git a/app/templates/admin/contenus.php b/app/templates/admin/contenus.php
index 4b64efd..d814704 100644
--- a/app/templates/admin/contenus.php
+++ b/app/templates/admin/contenus.php
@@ -53,8 +53,6 @@
         <section aria-labelledby="donnees-secondaires-title">
             <h2 id="donnees-secondaires-title">Données Secondaires</h2>
 
-            <p><a href="/admin/tags.php" class="btn btn--sm btn--primary">Gérer les mots-clés</a></p>
-
             <fieldset>
                 <legend>Langues</legend>
 
@@ -71,7 +69,34 @@
                 <div id="langues-table-wrap"
                      hx-get="/admin/contenus-langues-fragment.php"
                      hx-trigger="load"
-                     hx-swap="innerHTML">
+                     hx-swap="innerHTML"
+                     style="max-height:50vh;overflow-y:auto">
+                    <div style="padding:var(--space-m); text-align:center; color:var(--text-tertiary)">
+                        <img alt="Chargement…" class="htmx-indicator" width="24" src="/assets/img/bars.svg" style="opacity:0.5">
+                    </div>
+                </div>
+            </fieldset>
+
+            <p style="margin-top:var(--space-s)"><a href="/admin/tags.php" class="btn btn--sm btn--primary">Gérer les mots-clés (page dédiée)</a></p>
+
+            <fieldset>
+                <legend>Mots-clés</legend>
+
+                <form id="motscles-search-form"
+                      hx-get="/admin/contenus-motscles-fragment.php"
+                      hx-target="#motscles-table-wrap"
+                      hx-swap="innerHTML"
+                      hx-trigger="input changed delay:200ms from:input[name=q], keyup[key=='Enter'] from:input[name=q]"
+                      hx-push-url="false"
+                      style="margin-bottom:var(--space-xs)">
+                    <input type="text" name="q" placeholder="Rechercher un mot-clé…" style="max-width:300px">
+                </form>
+
+                <div id="motscles-table-wrap"
+                     hx-get="/admin/contenus-motscles-fragment.php"
+                     hx-trigger="load"
+                     hx-swap="innerHTML"
+                     style="max-height:50vh;overflow-y:auto">
                     <div style="padding:var(--space-m); text-align:center; color:var(--text-tertiary)">
                         <img alt="Chargement…" class="htmx-indicator" width="24" src="/assets/img/bars.svg" style="opacity:0.5">
                     </div>
@@ -349,6 +374,11 @@ function languesUpdateBulk() {
     document.getElementById('langues-bulk-actions').style.display = n > 1 ? 'flex' : 'none';
 }
 
+function languesCancelSelection() {
+    document.querySelectorAll('input[name="selected_langs[]"]').forEach(cb => cb.checked = false);
+    languesUpdateBulk();
+}
+
 function languesConfirmBulkMerge() {
     const checked = document.querySelectorAll('input[name="selected_langs[]"]:checked');
     if (checked.length < 2) return;
@@ -387,6 +417,137 @@ document.addEventListener('htmx:afterSwap', function(evt) {
 });
 </script>
 
+<!-- ═══════════════════════════════════════════════════════════════
+     CONFIRM DIALOGS FOR MOTS-CLÉS
+══════════════════════════════════════════════════════════════ -->
+
+<dialog id="motscles-delete-dialog" class="admin-dialog admin-dialog--sm" aria-labelledby="motscles-delete-title">
+    <div class="admin-dialog__header">
+        <h2 id="motscles-delete-title">Supprimer le mot-clé</h2>
+        <button type="button" class="admin-dialog__close" aria-label="Fermer"
+                onclick="this.closest('dialog').close()">&#x2715;</button>
+    </div>
+    <div class="admin-dialog__alert">
+        <p>Supprimer «&nbsp;<strong id="motscles-delete-name"></strong>&nbsp;»&nbsp;? Cette action est irréversible.</p>
+    </div>
+    <div class="admin-dialog__footer">
+        <button type="button" class="btn btn--danger" onclick="this.closest('dialog').close(); motsclesSubmitPending()">Supprimer</button>
+        <button type="button" class="btn btn--secondary" onclick="this.closest('dialog').close()">Annuler</button>
+    </div>
+</dialog>
+
+<dialog id="motscles-bulk-merge-dialog" class="admin-dialog admin-dialog--sm" aria-labelledby="motscles-bulk-merge-title">
+    <div class="admin-dialog__header">
+        <h2 id="motscles-bulk-merge-title">Fusionner des mots-clés</h2>
+        <button type="button" class="admin-dialog__close" aria-label="Fermer"
+                onclick="this.closest('dialog').close()">&#x2715;</button>
+    </div>
+    <div class="admin-dialog__alert">
+        <p>Fusionner <strong><span id="motscles-bulk-merge-count"></span> mot(s)-clé(s)</strong> sélectionné(s) dans&nbsp;:</p>
+        <select id="motscles-bulk-merge-target-select" class="admin-select--inline" style="margin-top:var(--space-xs); width:100%" required>
+            <option value="">— Choisir la destination —</option>
+        </select>
+    </div>
+    <div class="admin-dialog__footer">
+        <button type="button" class="btn btn--warning" onclick="motsclesExecBulkMerge()">Fusionner</button>
+        <button type="button" class="btn btn--secondary" onclick="this.closest('dialog').close()">Annuler</button>
+    </div>
+</dialog>
+
+<script>
+let _motsclesPendingForm = null;
+
+function motsclesConfirmDelete(btn, name) {
+    _motsclesPendingForm = btn.closest('form');
+    document.getElementById('motscles-delete-name').textContent = name;
+    document.getElementById('motscles-delete-dialog').showModal();
+}
+
+// ── Inline rename via HTMX ──────────────────────────────────────────────
+function motsclesStartRename(id) {
+    var cell = document.getElementById('motscles-name-' + id);
+    var csrf = document.querySelector('input[name="csrf_token"]').value;
+    cell.innerHTML = '<form hx-post="/admin/actions/tag.php" hx-target="#motscles-table-wrap" hx-swap="innerHTML" class="admin-inline-form">'
+        + '<input type="hidden" name="csrf_token" value="' + csrf + '">'
+        + '<input type="hidden" name="action" value="rename">'
+        + '<input type="hidden" name="return" value="/admin/contenus.php">'
+        + '<input type="hidden" name="tag_id" value="' + id + '">'
+        + '<input type="text" name="new_name" value="' + cell.getAttribute('data-name') + '" required class="admin-input--inline">'
+        + '<button type="submit" class="admin-icon-btn admin-icon-btn--edit" title="Valider">'
+        + '<svg xmlns="http://www.w3.org/2000/svg" width="32" height="32" fill="currentColor" viewBox="0 0 256 256"><path d="M229.66,77.66l-128,128a8,8,0,0,1-11.32,0l-56-56a8,8,0,0,1,11.32-11.32L96,188.69,218.34,66.34a8,8,0,0,1,11.32,11.32Z"/></svg>'
+        + '</button>'
+        + '<button type="button" class="admin-icon-btn admin-icon-btn--delete" onclick="motsclesCancelRename(' + id + ')" title="Annuler">'
+        + '<svg xmlns="http://www.w3.org/2000/svg" width="32" height="32" fill="currentColor" viewBox="0 0 256 256"><path d="M208.49,191.51a12,12,0,0,1-17,17L128,145,64.49,208.49a12,12,0,0,1-17-17L111,128,47.51,64.49a12,12,0,0,1,17-17L128,111l63.51-63.52a12,12,0,0,1,17,17L145,128Z"/></svg>'
+        + '</button></form>';
+    cell.querySelector('input').focus();
+}
+
+function motsclesCancelRename(id) {
+    var cell = document.getElementById('motscles-name-' + id);
+    cell.innerHTML = '<span class="tag-name-cell">' + cell.getAttribute('data-name') + '</span>'
+        + '<button type="button" class="admin-icon-btn admin-icon-btn--edit" title="Renommer" onclick="motsclesStartRename(' + id + ')">'
+        + '<svg xmlns="http://www.w3.org/2000/svg" width="32" height="32" fill="currentColor" viewBox="0 0 256 256"><path d="M248,92.68a15.86,15.86,0,0,0-4.69-11.31L174.63,12.68a16,16,0,0,0-22.63,0L123.57,41.11l-58,21.77A16.06,16.06,0,0,0,55.35,75.23L32.11,214.68A8,8,0,0,0,40,224a8.4,8.4,0,0,0,1.32-.11l139.44-23.24a16,16,0,0,0,12.35-10.17l21.77-58L243.31,104A15.87,15.87,0,0,0,248,92.68Zm-69.87,92.19L63.32,204l47.37-47.37a28,28,0,1,0-11.32-11.32L52,192.7,71.13,77.86,126,57.29,198.7,130ZM112,132a12,12,0,1,1,12,12A12,12,0,0,1,112,132Zm96-15.32L139.31,48l24-24L232,92.68Z"/></svg>'
+        + '</button>';
+}
+
+function motsclesSubmitPending() {
+    if (_motsclesPendingForm) _motsclesPendingForm.submit();
+}
+
+function motsclesToggleAll(src) {
+    document.querySelectorAll('input[name="selected_tags[]"]').forEach(cb => cb.checked = src.checked);
+    motsclesUpdateBulk();
+}
+
+function motsclesUpdateBulk() {
+    const n = document.querySelectorAll('input[name="selected_tags[]"]:checked').length;
+    document.getElementById('motscles-selected-count').textContent = n;
+    document.getElementById('motscles-bulk-actions').style.display = n > 1 ? 'flex' : 'none';
+}
+
+function motsclesConfirmBulkMerge() {
+    const checked = document.querySelectorAll('input[name="selected_tags[]"]:checked');
+    if (checked.length < 2) return;
+    document.getElementById('motscles-bulk-merge-count').textContent = checked.length;
+    const sel = document.getElementById('motscles-bulk-merge-target-select');
+    sel.innerHTML = '<option value="">— Choisir la destination —</option>';
+    checked.forEach(cb => {
+        const tr = cb.closest('tr');
+        sel.innerHTML += '<option value="' + cb.value + '">' + tr.querySelector('td:nth-child(2)').textContent.trim() + '</option>';
+    });
+    document.getElementById('motscles-bulk-merge-dialog').showModal();
+}
+
+function motsclesExecBulkMerge() {
+    const targetId = document.getElementById('motscles-bulk-merge-target-select').value;
+    if (!targetId) return;
+    document.getElementById('motscles-bulk-target').value = targetId;
+    const container = document.getElementById('motscles-bulk-checkboxes');
+    container.innerHTML = '';
+    document.querySelectorAll('input[name="selected_tags[]"]:checked').forEach(cb => {
+        const inp = document.createElement('input');
+        inp.type = 'hidden';
+        inp.name = 'selected_tags[]';
+        inp.value = cb.value;
+        container.appendChild(inp);
+    });
+    document.getElementById('motscles-bulk-merge-dialog').close();
+    document.getElementById('motscles-bulk-form').submit();
+}
+
+function motsclesCancelSelection() {
+    document.querySelectorAll('input[name="selected_tags[]"]').forEach(cb => cb.checked = false);
+    motsclesUpdateBulk();
+}
+
+document.addEventListener('htmx:afterSwap', function(evt) {
+    if (evt.target.id === 'motscles-table-wrap') {
+        document.querySelectorAll('input[name="selected_tags[]"]').forEach(cb => cb.addEventListener('change', motsclesUpdateBulk));
+        motsclesUpdateBulk();
+    }
+});
+</script>
+
 <script>
 (function () {
     var otScript = document.createElement('script');