diff --git a/canaille/account.py b/canaille/account.py
index 85e494bd..25e08c65 100644
--- a/canaille/account.py
+++ b/canaille/account.py
@@ -159,11 +159,7 @@ def firstlogin(uid):
 @bp.route("/users")
 @permissions_needed("manage_users")
 def users(user):
-    users = User.filter(
-        objectClass=current_app.config["LDAP"].get(
-            "USER_CLASS", User.DEFAULT_OBJECT_CLASS
-        )
-    )
+    users = User.filter()
     return render_template("users.html", users=users, menuitem="users")
 
 
diff --git a/canaille/groups.py b/canaille/groups.py
index 8f2528ff..3e284986 100644
--- a/canaille/groups.py
+++ b/canaille/groups.py
@@ -19,11 +19,7 @@ bp = Blueprint("groups", __name__, url_prefix="/groups")
 @bp.route("/")
 @permissions_needed("manage_groups")
 def groups(user):
-    groups = Group.filter(
-        objectClass=current_app.config["LDAP"].get(
-            "GROUP_CLASS", Group.DEFAULT_OBJECT_CLASS
-        )
-    )
+    groups = Group.filter()
     return render_template("groups.html", groups=groups, menuitem="groups")
 
 
diff --git a/canaille/ldap_backend/backend.py b/canaille/ldap_backend/backend.py
index 91b39f43..7809a94f 100644
--- a/canaille/ldap_backend/backend.py
+++ b/canaille/ldap_backend/backend.py
@@ -21,12 +21,18 @@ def setup_ldap_models(app):
         user_base = user_base[: -len(app.config["LDAP"]["ROOT_DN"]) - 1]
     User.base = user_base
     User.id = app.config["LDAP"].get("USER_ID_ATTRIBUTE", User.DEFAULT_ID_ATTRIBUTE)
+    User.object_class = [
+        app.config["LDAP"].get("USER_CLASS", User.DEFAULT_OBJECT_CLASS)
+    ]
 
     group_base = app.config["LDAP"].get("GROUP_BASE")
     if group_base.endswith(app.config["LDAP"]["ROOT_DN"]):
         group_base = group_base[: -len(app.config["LDAP"]["ROOT_DN"]) - 1]
     Group.base = group_base
     Group.id = app.config["LDAP"].get("GROUP_ID_ATTRIBUTE", Group.DEFAULT_ID_ATTRIBUTE)
+    Group.object_class = [
+        app.config["LDAP"].get("GROUP_CLASS", Group.DEFAULT_OBJECT_CLASS)
+    ]
 
 
 def setup_backend(app):
diff --git a/canaille/models.py b/canaille/models.py
index 4a25a3c1..e1105d22 100644
--- a/canaille/models.py
+++ b/canaille/models.py
@@ -188,18 +188,15 @@ class Group(LDAPObject):
     def available_groups(cls, conn=None):
         conn = conn or cls.ldap()
         try:
-            attribute = current_app.config["LDAP"].get(
+            name_attribute = current_app.config["LDAP"].get(
                 "GROUP_NAME_ATTRIBUTE", Group.DEFAULT_NAME_ATTRIBUTE
             )
-            object_class = current_app.config["LDAP"].get(
-                "GROUP_CLASS", Group.DEFAULT_OBJECT_CLASS
-            )
         except KeyError:
             return []
 
-        groups = cls.filter(objectClass=object_class, conn=conn)
+        groups = cls.filter(conn=conn)
         Group.ldap_object_attributes(conn=conn)
-        return [(group[attribute][0], group.dn) for group in groups]
+        return [(group[name_attribute][0], group.dn) for group in groups]
 
     @property
     def name(self):