diff --git a/payroll.py b/payroll.py
index 6c87bf4..0198c83 100644
--- a/payroll.py
+++ b/payroll.py
@@ -424,7 +424,7 @@ class Payroll(Workflow, ModelSQL, ModelView):
                 unit_value = fix_amount
 
             discount = None
-            if discounts.get(wage.id):
+            if discounts and discounts.get(wage.id):
                 discount = discounts.get(wage.id)
             qty = self.get_line_quantity_special(wage)
             if qty == 0: