diff --git a/synapse/handlers/federation.py b/synapse/handlers/federation.py
index 692c2d8a7b..f52eb1205b 100644
--- a/synapse/handlers/federation.py
+++ b/synapse/handlers/federation.py
@@ -179,6 +179,7 @@ class FederationHandler(BaseHandler):
                     context=event.room_id,
                     event_id=event.event_id,
                 )
+                # FIXME: Get auth chain for these state events
 
             current_state = state