diff --git a/mongoengine/fields.py b/mongoengine/fields.py
index 418f57cc..87d52fd6 100644
--- a/mongoengine/fields.py
+++ b/mongoengine/fields.py
@@ -528,6 +528,7 @@ class GridFSProxy(object):
         obj = self.get()
         if name in dir(obj):
             return getattr(obj, name)
+        raise AttributeError
 
     def __get__(self, instance, value):
         return self