diff --git a/auquotidien/modules/payments.py b/auquotidien/modules/payments.py
index 0de01a4..316db45 100644
--- a/auquotidien/modules/payments.py
+++ b/auquotidien/modules/payments.py
@@ -176,6 +176,8 @@ class InvoiceEvolutionPart:
             'subject': self.subject,
             'amount': self.amount,
         }
+        if not self.action:
+            return ''
         if self.transaction:
             vars['transaction_order_id'] = self.transaction.order_id
         return htmltext('<p class="invoice-%s">' % self.action + \