On fixe le cas des événements sans description

src/agenda_culturel/models.py

@@ -2026,7 +2026,7 @@ class CategorisationRule(models.Model):
             if self.desc_exact:
                 result = self.description_contains in event.description
             else:
-                result = (
+                result = event.description and (
                     remove_accents(self.description_contains).lower()
                     in remove_accents(event.description).lower()
                 )