diff --git a/openerp/addons/base/ir/ir_model.py b/openerp/addons/base/ir/ir_model.py
index ec89fe8bc70..d71622727c5 100644
--- a/openerp/addons/base/ir/ir_model.py
+++ b/openerp/addons/base/ir/ir_model.py
@@ -385,7 +385,7 @@ class ir_model_fields(osv.osv):
 
         # static table of properties
         model_props = [ # (our-name, fields.prop, set_fn)
-            ('field_description', 'string', str),
+            ('field_description', 'string', tools.ustr),
             ('required', 'required', bool),
             ('readonly', 'readonly', bool),
             ('domain', '_domain', eval),