diff --git a/addons/account/wizard/account_tax_chart.py b/addons/account/wizard/account_tax_chart.py
index 5b5feaf480c..1595a603dd0 100644
--- a/addons/account/wizard/account_tax_chart.py
+++ b/addons/account/wizard/account_tax_chart.py
@@ -37,7 +37,8 @@ class account_tax_chart(osv.osv_memory):
 
     def _get_period(self, cr, uid, context=None):
         """Return default period value"""
-        return self.pool.get('account.period').find(cr, uid)
+        period_ids = self.pool.get('account.period').find(cr, uid)
+        return period_ids and period_ids[0] or False
 
     def account_tax_chart_open_window(self, cr, uid, ids, context=None):
         """