diff --git a/addons/account/models/account_move.py b/addons/account/models/account_move.py
index e6c13c71d68..3cb6e528a57 100644
--- a/addons/account/models/account_move.py
+++ b/addons/account/models/account_move.py
@@ -3633,3 +3633,9 @@ class AccountMove(models.Model):
         :returns:       A list of tuples (priority, method) where method takes an attachment as parameter.
         """
         return []
+
+    def _is_downpayment(self):
+        ''' Return true if the invoice is a downpayment.
+        Down-payments can be created from a sale order. This method is overridden in the sale order module.
+        '''
+        return False
diff --git a/addons/account/models/account_move_line.py b/addons/account/models/account_move_line.py
index 2f8935d5c27..889b4892301 100644
--- a/addons/account/models/account_move_line.py
+++ b/addons/account/models/account_move_line.py
@@ -2589,3 +2589,9 @@ class AccountMoveLine(models.Model):
 
     def _copy_data_extend_business_fields(self, values):
         self.ensure_one()
+
+    def _get_downpayment_lines(self):
+        ''' Return the downpayment move lines associated with the move line.
+        This method is overridden in the sale order module.
+        '''
+        return self.env['account.move.line']
diff --git a/addons/sale/models/account_move.py b/addons/sale/models/account_move.py
index cb3f4ad6b9f..ad38e69cd33 100644
--- a/addons/sale/models/account_move.py
+++ b/addons/sale/models/account_move.py
@@ -125,3 +125,8 @@ class AccountMove(models.Model):
         else:
             result = {'type': 'ir.actions.act_window_close'}
         return result
+
+    def _is_downpayment(self):
+        # OVERRIDE
+        self.ensure_one()
+        return self.line_ids.sale_line_ids and all(sale_line.is_downpayment for sale_line in self.line_ids.sale_line_ids) or False
diff --git a/addons/sale/models/account_move_line.py b/addons/sale/models/account_move_line.py
index b36ef138b7c..27f559bbd0a 100644
--- a/addons/sale/models/account_move_line.py
+++ b/addons/sale/models/account_move_line.py
@@ -203,3 +203,7 @@ class AccountMoveLine(models.Model):
         if currency_id and currency_id != order.currency_id:
             price_unit = currency_id._convert(price_unit, order.currency_id, order.company_id, order.date_order or fields.Date.today())
         return price_unit
+
+    def _get_downpayment_lines(self):
+        # OVERRIDE
+        return self.sale_line_ids.filtered('is_downpayment').invoice_lines.filtered(lambda line: line.move_id._is_downpayment())