diff --git a/invoice.py b/invoice.py
index 8049c092ec..ccac4ef1cc 100644
--- a/invoice.py
+++ b/invoice.py
@@ -989,12 +989,12 @@ class Invoice(Workflow, ModelSQL, ModelView):
     @classmethod
     def search_rec_name(cls, name, clause):
         invoices = cls.search(['OR',
-                ('number',) + clause[1:],
-                ('reference',) + clause[1:],
+                ('number',) + tuple(clause[1:]),
+                ('reference',) + tuple(clause[1:]),
                 ], order=[])
         if invoices:
             return [('id', 'in', [i.id for i in invoices])]
-        return [('party',) + clause[1:]]
+        return [('party',) + tuple(clause[1:])]
 
     @classmethod
     def get_origins(cls, invoices, name):