diff --git a/synapse/rest/client/v1/push_rule.py b/synapse/rest/client/v1/push_rule.py
index 6c8f09e898..d26e4cde3e 100644
--- a/synapse/rest/client/v1/push_rule.py
+++ b/synapse/rest/client/v1/push_rule.py
@@ -324,7 +324,9 @@ def _filter_ruleset_with_path(ruleset, path):
 
     attr = path[0]
     if attr in the_rule:
-        return the_rule[attr]
+        # Make sure we return a JSON object as the attribute may be a
+        # JSON value.
+        return {attr: the_rule[attr]}
     else:
         raise UnrecognizedRequestError()