diff --git a/plugin/ims_lti/ImsLtiPlugin.php b/plugin/ims_lti/ImsLtiPlugin.php
index c996b9fd56..2b144ea6bd 100644
--- a/plugin/ims_lti/ImsLtiPlugin.php
+++ b/plugin/ims_lti/ImsLtiPlugin.php
@@ -543,4 +543,17 @@ class ImsLtiPlugin extends Plugin
             }
         }
     }
+
+    /**
+     * Avoid conflict with foreign key when deleting a course
+     *
+     * @param int $courseId
+     */
+    public function doWhenDeletingCourse($courseId)
+    {
+        $em = Database::getManager();
+
+        $em->createQuery('DELETE FROM ChamiloPluginBundle:ImsLti\ImsLtiTool tool WHERE tool.course = :c_id')
+            ->execute(['c_id' => (int) $courseId]);
+    }
 }
diff --git a/plugin/studentfollowup/StudentFollowUpPlugin.php b/plugin/studentfollowup/StudentFollowUpPlugin.php
index 26864c78a3..032ddc9d36 100644
--- a/plugin/studentfollowup/StudentFollowUpPlugin.php
+++ b/plugin/studentfollowup/StudentFollowUpPlugin.php
@@ -240,4 +240,15 @@ class StudentFollowUpPlugin extends Plugin
     {
         return 20;
     }
+
+    /**
+     * @param int $userId
+     */
+    public function doWhenDeletingUser($userId)
+    {
+        $userId = (int) $userId;
+
+        Database::query("DELETE FROM sfu_post WHERE user_id = $userId");
+        Database::query("DELETE FROM sfu_post WHERE insert_user_id = $userId");
+    }
 }