diff --git a/src/Application/Actions/Group/AddUserGroupAction.php b/src/Application/Actions/Group/AddUserGroupAction.php
index 04155ee646c865f1c02a1fbfda4423a99693c10b..cff8adf5f3df9bda27e49a9118e54c7f28a1eec7 100755
--- a/src/Application/Actions/Group/AddUserGroupAction.php
+++ b/src/Application/Actions/Group/AddUserGroupAction.php
@@ -20,7 +20,13 @@ class AddUserGroupAction extends GroupAction
         if (!isset($group)) {
             throw new GroupNotFoundException();
         }
+    
         $currentUser = $this->userRepository->find($_SESSION['userId']);
+        if ($this->group->hasUser($currentUser)){
+            return $this->response
+            ->withHeader('Location', '/groups/' . $groupId)
+            ->withStatus(302);
+        }
         $currentUser->addGroup($group);        
 
         $this->em->persist($group);