diff --git a/app/scodoc/sco_preferences.py b/app/scodoc/sco_preferences.py
index 72c9d705..6e0cfdeb 100644
--- a/app/scodoc/sco_preferences.py
+++ b/app/scodoc/sco_preferences.py
@@ -2333,7 +2333,7 @@ class BasePreferences:
                             <option value="create">Spécifier valeur pour ce
                             semestre seulement</option>
                         </select>
-                        <span class="pref-comment">{descr["comment"]}</span>
+                        <span class="pref-comment">{descr["comment"] or ''}</span>
                         """
                         descr["explanation"] = menu_global