diff --git a/openslides/assignment/views.py b/openslides/assignment/views.py
index 68f561c87..a65d10997 100644
--- a/openslides/assignment/views.py
+++ b/openslides/assignment/views.py
@@ -430,7 +430,7 @@ class AssignmentPDF(PDFView):
         for candidate, poll_list in vote_results.iteritems():
             row = []
 
-            candidate_string = candidate.user.get_full_name()
+            candidate_string = candidate.clean_name
             if candidate in elected_candidates:
                 candidate_string = "* " + candidate_string
             if candidate.category:
@@ -565,7 +565,7 @@ class AssignmentPollPDF(PDFView):
         if self.poll.yesnoabstain:
             for option in options:
                 candidate = option.candidate
-                cell.append(Paragraph(candidate.user.get_full_name(),
+                cell.append(Paragraph(candidate.clean_name,
                     stylesheet['Ballot_option_name']))
                 if candidate.name_suffix:
                     cell.append(Paragraph("(%s)" % candidate.name_suffix,
@@ -591,9 +591,9 @@ class AssignmentPollPDF(PDFView):
         else:
             for option in options:
                 candidate = option.candidate
-                cell.append(Paragraph(circle + candidate.user.get_full_name(),
+                cell.append(Paragraph(circle + candidate.clean_name,
                     stylesheet['Ballot_option_name']))
-                if candidate.category:
+                if candidate.name_suffix:
                     cell.append(Paragraph("(%s)" % candidate.category,
                         stylesheet['Ballot_option_group_right']))
                 else:
diff --git a/openslides/participant/models.py b/openslides/participant/models.py
index 42b965f69..2cce07709 100644
--- a/openslides/participant/models.py
+++ b/openslides/participant/models.py
@@ -16,14 +16,14 @@ from django.db.models import signals
 from django.dispatch import receiver
 from django.utils.translation import ugettext_lazy as _, ugettext_noop
 
-from openslides.utils.person import PersonMixin
+from openslides.utils.person import PersonMixin, Person
 from openslides.utils.person.signals import receive_persons
 
 from openslides.config.models import config
 from openslides.config.signals import default_config_value
 
 
-class User(DjangoUser, PersonMixin):
+class User(DjangoUser, PersonMixin, Person):
     person_prefix = 'user'
     GENDER_CHOICES = (
         ('male', _('Male')),
@@ -56,6 +56,10 @@ class User(DjangoUser, PersonMixin):
         max_length=100, null=True, blank=True,
         verbose_name=_("Default password"))
 
+    @property
+    def clean_name(self):
+        return self.get_full_name() or self.username
+
     def get_name_suffix(self):
         return self.category
 
@@ -88,10 +92,9 @@ class User(DjangoUser, PersonMixin):
             return ('user_delete', [str(self.id)])
 
     def __unicode__(self):
-        name = self.get_full_name() or self.username
         if self.name_suffix:
-            return u"%s (%s)" % (name, self.name_suffix)
-        return u"%s" % name
+            return u"%s (%s)" % (self.clean_name, self.name_suffix)
+        return u"%s" % self.clean_name
 
     class Meta:
         # Rename permissions
@@ -103,7 +106,7 @@ class User(DjangoUser, PersonMixin):
         ordering = ('last_name',)
 
 
-class Group(DjangoGroup, PersonMixin):
+class Group(DjangoGroup, PersonMixin, Person):
     person_prefix = 'group'
 
     django_group = models.OneToOneField(DjangoGroup, editable=False, parent_link=True)
diff --git a/openslides/utils/person/__init__.py b/openslides/utils/person/__init__.py
index cc983caf9..7a69e8f25 100644
--- a/openslides/utils/person/__init__.py
+++ b/openslides/utils/person/__init__.py
@@ -11,7 +11,8 @@
 """
 
 from openslides.utils.person.signals import receive_persons
-from openslides.utils.person.api import generate_person_id, get_person, Persons
+from openslides.utils.person.api import (generate_person_id, get_person,
+    Person, Persons)
 from openslides.utils.person.forms import PersonFormField, MultiplePersonFormField
 from openslides.utils.person.models import PersonField, PersonMixin
 
diff --git a/openslides/utils/person/api.py b/openslides/utils/person/api.py
index 49d901f28..5c842dea2 100644
--- a/openslides/utils/person/api.py
+++ b/openslides/utils/person/api.py
@@ -13,6 +13,37 @@
 from openslides.utils.person.signals import receive_persons
 
 
+class Person(object):
+    """
+    Meta-class for all person objects
+    """
+    def person_id(self):
+        """
+        Return an id for representation of ths person. Has to be unique.
+        """
+        raise NotImplementedError('Any person object needs a person_id')
+
+    def __repr__(self):
+        """
+        Return a string for this person.
+        """
+        return str(self.person_id)
+
+    @property
+    def clean_name(self):
+        """
+        Return the name of this person without a suffix
+        """
+        return unicode(self)
+
+    @property
+    def name_suffix(self):
+        """
+        Return a suffix for the person-name.
+        """
+        return ''
+
+
 class Persons(object):
     """
     A Storage for a multiplicity of different Person-Objects.