diff --git a/addons/sale/tests/test_sale_to_invoice.py b/addons/sale/tests/test_sale_to_invoice.py
index 43a93344ef6..c1d2f261790 100644
--- a/addons/sale/tests/test_sale_to_invoice.py
+++ b/addons/sale/tests/test_sale_to_invoice.py
@@ -197,6 +197,38 @@ class TestSaleToInvoice(TestSaleCommon):
         downpayment_line = sale_order.order_line.filtered(lambda l: l.is_downpayment and not l.display_type)
         self.assertEqual(downpayment_line[0].price_unit, 50, 'The down payment unit price should not change on SO')
 
+    def test_downpayment_fixed_amount_with_zero_total_amount(self):
+        # Create the SO with one line and amount total is zero
+        sale_order = self.env['sale.order'].with_context(tracking_disable=True).create({
+            'partner_id': self.partner_a.id,
+            'partner_invoice_id': self.partner_a.id,
+            'partner_shipping_id': self.partner_a.id,
+            'pricelist_id': self.company_data['default_pricelist'].id,
+            'order_line': [Command.create({
+                'product_id': self.company_data['product_order_no'].id,
+                'product_uom_qty': 5,
+                'price_unit': 0,
+                'tax_id': False,
+            }), ]
+        })
+        sale_order.action_confirm()
+        sale_order.order_line.write({'qty_delivered': 5.0})
+        context = {
+            'active_model': 'sale.order',
+            'active_ids': [sale_order.id],
+            'active_id': sale_order.id,
+            'default_journal_id': self.company_data['default_journal_sale'].id,
+        }
+        # Let's do an invoice for a down payment of 50
+        downpayment = self.env['sale.advance.payment.inv'].with_context(context).create({
+            'advance_payment_method': 'fixed',
+            'fixed_amount': 50,
+            'deposit_account_id': self.company_data['default_account_revenue'].id
+        })
+        # Create invoice
+        downpayment.create_invoices()
+        self.assertEqual(downpayment.amount, 0.0, 'The down payment amount should be 0.0')
+
     def test_downpayment_percentage_tax_icl(self):
         """ Test invoice with a percentage downpayment and an included tax
             Check the total amount of invoice is correct and equal to a respective sale order's total amount
diff --git a/addons/sale/wizard/sale_make_invoice_advance.py b/addons/sale/wizard/sale_make_invoice_advance.py
index ec1801b7162..5730a7b3eec 100644
--- a/addons/sale/wizard/sale_make_invoice_advance.py
+++ b/addons/sale/wizard/sale_make_invoice_advance.py
@@ -282,7 +282,7 @@ class SaleAdvancePaymentInv(models.TransientModel):
         if self.advance_payment_method == 'percentage':
             percentage = self.amount / 100
         else:
-            percentage = self.fixed_amount / order.amount_total
+            percentage = self.fixed_amount / order.amount_total if order.amount_total else 1
 
         order_lines = order.order_line.filtered(lambda l: not l.display_type)
         base_downpayment_lines_values = self._prepare_base_downpayment_line_values(order)