diff --git a/app/app.py b/app/app.py
index bcf98f6..1a6c410 100644
--- a/app/app.py
+++ b/app/app.py
@@ -531,6 +531,30 @@ def rename_file():
     })
 
 
+# ── Vérification des conflits avant upload ───────────────────────────
+
+@app.route("/check-upload", methods=["POST"])
+def check_upload():
+    redir = _require_admin()
+    if redir:
+        return redir
+
+    subpath = request.form.get("path", "").strip()
+    names   = request.form.getlist("names")
+
+    if subpath:
+        parts = Path(subpath).parts
+        if parts and (parts[0] in _HIDDEN or parts[0].startswith(".")):
+            abort(403)
+
+    dest = _safe_path(subpath) if subpath else ASSETS_ROOT
+    if not dest.is_dir():
+        abort(400)
+
+    conflicts = [n for n in names if n and (dest / secure_filename(n)).exists()]
+    return jsonify({"conflicts": conflicts})
+
+
 # ── Upload de fichiers ────────────────────────────────────────────────
 
 @app.route("/upload", methods=["POST"])
diff --git a/app/static/app.css b/app/static/app.css
index d888214..8a0be89 100644
--- a/app/static/app.css
+++ b/app/static/app.css
@@ -165,7 +165,10 @@ main { max-width: 1100px; margin: 2rem auto; padding: 0 1.5rem 3rem; display: fl
 
 /* ── Upload ───────────────────────────────────────────────────────── */
 .upload-card h2 { margin-bottom: .8rem; }
-.upload-conflict { display: flex; align-items: center; gap: .8rem; flex-wrap: wrap; margin-bottom: .8rem; }
+
+.conflict-panel { margin-top: .9rem; padding: 1rem 1.2rem; background: #fffbeb; border: 1px solid #fcd34d; border-radius: var(--radius); display: flex; flex-direction: column; gap: .7rem; }
+.conflict-title { font-size: .88rem; color: #92400e; }
+.conflict-actions { display: flex; align-items: center; gap: .8rem; }
 .drop-zone { display: flex; flex-direction: column; align-items: center; justify-content: center; gap: .5rem; border: 2px dashed var(--border); border-radius: var(--radius); padding: 2rem 1.5rem; cursor: pointer; background: var(--bg); transition: border-color .15s, background .15s; text-align: center; position: relative; margin-bottom: 1rem; }
 .drop-zone:hover, .drop-zone:focus-within { border-color: var(--blue); background: var(--blue-light); }
 .drop-zone input[type=file] { position: absolute; inset: 0; opacity: 0; cursor: pointer; width: 100%; height: 100%; }
diff --git a/app/templates/browse.html b/app/templates/browse.html
index 71210ef..523411c 100644
--- a/app/templates/browse.html
+++ b/app/templates/browse.html
@@ -120,26 +120,81 @@
       <span class="drop-names" id="drop-names"></span>
       <input type="file" name="files" id="upload-input" multiple>
     </label>
-    <div class="upload-conflict">
-      <span class="resize-group-label">Si le fichier existe déjà</span>
+    <input type="hidden" name="conflict" id="conflict-value" value="overwrite">
+    <button type="submit" class="btn btn-primary" id="upload-btn" disabled>Envoyer</button>
+
+    <div id="upload-conflict-panel" class="conflict-panel" style="display:none">
+      <p class="conflict-title">⚠ Ces fichiers existent déjà : <strong id="conflict-list"></strong></p>
       <div class="resize-chips resize-chips--radio">
-        <label class="chip"><input type="radio" name="conflict" value="overwrite" checked><span>Écraser</span></label>
-        <label class="chip"><input type="radio" name="conflict" value="backup"><span>Backup</span></label>
-        <label class="chip"><input type="radio" name="conflict" value="rename"><span>Renommer</span></label>
-        <label class="chip"><input type="radio" name="conflict" value="skip"><span>Ignorer</span></label>
+        <label class="chip"><input type="radio" name="conflict-choice" value="overwrite" checked><span>Écraser</span></label>
+        <label class="chip"><input type="radio" name="conflict-choice" value="backup"><span>Backup</span></label>
+        <label class="chip"><input type="radio" name="conflict-choice" value="rename"><span>Renommer</span></label>
+        <label class="chip"><input type="radio" name="conflict-choice" value="skip"><span>Ignorer</span></label>
+      </div>
+      <div class="conflict-actions">
+        <button type="button" id="conflict-confirm" class="btn btn-primary">Confirmer l'envoi</button>
+        <button type="button" id="conflict-cancel"  class="btn-rename-cancel">Annuler</button>
       </div>
     </div>
-    <button type="submit" class="btn btn-primary" id="upload-btn" disabled>Envoyer</button>
   </form>
   <script>
-    const inp  = document.getElementById('upload-input');
-    const btn  = document.getElementById('upload-btn');
-    const lbl  = document.getElementById('drop-names');
-    inp.addEventListener('change', () => {
-      const n = inp.files.length;
-      lbl.textContent = n ? Array.from(inp.files).map(f => f.name).join(', ') : '';
-      btn.disabled = n === 0;
-    });
+    (function () {
+      const form    = document.getElementById('upload-form');
+      const inp     = document.getElementById('upload-input');
+      const btn     = document.getElementById('upload-btn');
+      const lbl     = document.getElementById('drop-names');
+      const panel   = document.getElementById('upload-conflict-panel');
+      const hidden  = document.getElementById('conflict-value');
+      const listEl  = document.getElementById('conflict-list');
+      const confirm = document.getElementById('conflict-confirm');
+      const cancel  = document.getElementById('conflict-cancel');
+      const PATH    = {{ subpath | tojson }};
+      let resolved  = false;
+
+      inp.addEventListener('change', () => {
+        const n = inp.files.length;
+        lbl.textContent = n ? Array.from(inp.files).map(f => f.name).join(', ') : '';
+        btn.disabled = n === 0;
+        panel.style.display = 'none';
+        resolved = false;
+      });
+
+      form.addEventListener('submit', async (e) => {
+        if (resolved) return;
+        e.preventDefault();
+
+        const names = Array.from(inp.files).map(f => f.name);
+        let conflicts = [];
+        try {
+          const fd = new FormData();
+          fd.append('path', PATH);
+          names.forEach(n => fd.append('names', n));
+          const resp = await fetch({{ url_for('check_upload') | tojson }}, { method: 'POST', body: fd });
+          const data = await resp.json();
+          conflicts = data.conflicts || [];
+        } catch (_) { /* réseau : on laisse passer */ }
+
+        if (!conflicts.length) {
+          resolved = true;
+          form.submit();
+          return;
+        }
+
+        listEl.textContent = conflicts.join(', ');
+        panel.style.display = 'block';
+        panel.scrollIntoView({ behavior: 'smooth', block: 'nearest' });
+      });
+
+      confirm.addEventListener('click', () => {
+        hidden.value = document.querySelector('input[name="conflict-choice"]:checked').value;
+        resolved = true;
+        form.submit();
+      });
+
+      cancel.addEventListener('click', () => {
+        panel.style.display = 'none';
+      });
+    })();
   </script>
 </section>