diff --git a/product/ERP5Type/Base.py b/product/ERP5Type/Base.py
index c4a8b02211e6ca011e9423cab72d8d7b783a5b5e..555bfe5f7cb0fa23f7f471c10efc9e87a01ff373 100644
--- a/product/ERP5Type/Base.py
+++ b/product/ERP5Type/Base.py
@@ -650,7 +650,7 @@ class Base( CopyContainer,
     if storage_id is None: storage_id=key
     #LOG("Get Acquired Property storage_id",0,str(storage_id))
     # If we hold an attribute and mask_value is set, return the attribute
-    value = getattr(self, storage_id, None)
+    value = getattr(aq_base(self), storage_id, None)
     if mask_value and value is not None:
       # Pop context
       del TRANSACTION._erp5_acquisition_stack[acquisition_key]