diff --git a/edbob/db/extensions/auth/model.py b/edbob/db/extensions/auth/model.py
index 5b5f122..a3f36f0 100644
--- a/edbob/db/extensions/auth/model.py
+++ b/edbob/db/extensions/auth/model.py
@@ -53,8 +53,8 @@ class Permission(Base):
     def __repr__(self):
         return "<Permission: %s, %s>" % (self.role, self.permission)
 
-    def __str__(self):
-        return str(self.permission or '')
+    def __unicode__(self):
+        return unicode(self.permission or '')
 
 
 class UserRole(Base):
@@ -99,8 +99,8 @@ class Role(Base):
     def __repr__(self):
         return "<Role: %s>" % self.name
 
-    def __str__(self):
-        return str(self.name or '')
+    def __unicode__(self):
+        return unicode(self.name or '')
 
 
 class User(Base):
@@ -126,15 +126,16 @@ class User(Base):
     def __repr__(self):
         return "<User: %s>" % self.username
 
-    def __str__(self):
-        return str(self.username or '')
+    def __unicode__(self):
+        return unicode(self.username or '')
 
     @property
     def display_name(self):
         """
-        Returns the user's ``person.display_name``, if present, otherwise the
-        ``username``.
+        Returns :attr:`Person.display_name` if present; otherwise returns
+        :attr:`username`.
         """
+
         if self.person and self.person.display_name:
             return self.person.display_name
         return self.username