diff --git a/frontend/js/auth.js b/frontend/js/auth.js
index b0f04da..ba08c06 100644
--- a/frontend/js/auth.js
+++ b/frontend/js/auth.js
@@ -294,6 +294,19 @@ function initLoginForm() {
     try {
       await AuthManager.login(username, password, rememberMe);
       AuthManager.showApp();
+
+      // Re-sync language from server now that we're authenticated
+      try {
+        const resp = await fetch('/api/auth/me', { credentials: 'include' });
+        if (resp.ok) {
+          const user = await resp.json();
+          if (user.language && user.language !== getLocale()) {
+            const { setLocale } = await import('./i18n.js');
+            await setLocale(user.language);
+          }
+        }
+      } catch (e) { /* non-bloquant */ }
+
       // Load app data after successful login
       try {
         await Promise.all([loadVaults(), loadTags()]);