diff --git a/openslides/assignment/models.py b/openslides/assignment/models.py
index c88f735cc..2e060dc79 100644
--- a/openslides/assignment/models.py
+++ b/openslides/assignment/models.py
@@ -15,7 +15,7 @@ from django.utils.translation import ugettext as _
 
 from participant.models import Profile
 
-from projector.models import SlideMixin
+from projector.projector import SlideMixin
 from projector.api import register_slidemodel
 from poll.models import BasePoll, CountInvalid, CountVotesCast, BaseOption, PublishPollMixin