diff --git a/ops/framework.py b/ops/framework.py
index 1b71d68f5..661c6959d 100644
--- a/ops/framework.py
+++ b/ops/framework.py
@@ -951,9 +951,9 @@ def _reemit(self, single_event_path: Optional[str] = None):
 
             else:
                 logger.warning(
-                    f'Reference to ops.Object at path {observer_path} has been garbage collected '
+                    'Reference to ops.Object at path %s has been garbage collected '
                     'between when the charm was initialised and when the event was emitted. '
-                    'Make sure sure you store a reference to the observer.'
+                    'Make sure sure you store a reference to the observer.', observer_path
                 )
 
             if event.deferred: