diff --git a/addons/website_sale/controllers/main.py b/addons/website_sale/controllers/main.py
index 46654ede3e2..fcc9ce29fff 100644
--- a/addons/website_sale/controllers/main.py
+++ b/addons/website_sale/controllers/main.py
@@ -817,8 +817,9 @@ class website_sale(http.Controller):
             composer_values.update(composer_obj.onchange_template_id(cr, SUPERUSER_ID, None, *template_values, context=context).get('value', {}))
             if not composer_values.get('email_from') and uid == request.website.user_id.id:
                 composer_values['email_from'] = request.website.user_id.company_id.email
-            if composer_values.get('attachment_ids'):
-                composer_values['attachment_ids'] = [(6, 0, composer_values['attachment_ids'])]
+            for key in ['attachment_ids', 'partner_ids']:
+                if composer_values.get(key):
+                    composer_values[key] = [(6, 0, composer_values[key])]
             composer_id = composer_obj.create(cr, SUPERUSER_ID, composer_values, context=email_ctx)
             composer_obj.send_mail(cr, SUPERUSER_ID, [composer_id], context=email_ctx)