diff --git a/openslides/agenda/models.py b/openslides/agenda/models.py
index 7adf1af52..f1ee02de0 100644
--- a/openslides/agenda/models.py
+++ b/openslides/agenda/models.py
@@ -302,7 +302,7 @@ class SpeakerManager(models.Manager):
         """
         if self.filter(user=user, item=item, begin_time=None).exists():
             raise OpenSlidesError(
-                _('{user} is already on the list of speakers.').format(user=user)
+                _('{user} is already on the list of speakers.').format(user=user))
         if isinstance(user, AnonymousUser):
             raise OpenSlidesError(
                 _('An anonymous user can not be on lists of speakers.'))