diff --git a/addons/account/wizard/wizard_pay_invoice.py b/addons/account/wizard/wizard_pay_invoice.py
index 706f3f92b10..ed7f23013ec 100644
--- a/addons/account/wizard/wizard_pay_invoice.py
+++ b/addons/account/wizard/wizard_pay_invoice.py
@@ -108,7 +108,7 @@ def _get_period(self, cr, uid, data, context={}):
 		period_id = ids[0]
 	invoice = pool.get('account.invoice').browse(cr, uid, data['id'], context)
 	if invoice.state == 'draft':
-		raise wizard.except_wizard('Error !', 'Can not pay draft invoice.')
+		raise wizard.except_wizard('Error !', _('Can not pay draft invoice.'))
 	return {
 		'period_id': period_id,
 		'amount': invoice.amount_total,