diff --git a/l10n_pt_sale_downpayment/README.rst b/l10n_pt_sale_downpayment/README.rst
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+++ b/l10n_pt_sale_downpayment/README.rst
@@ -0,0 +1 @@
+TODO
diff --git a/l10n_pt_sale_downpayment/__init__.py b/l10n_pt_sale_downpayment/__init__.py
new file mode 100644
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+++ b/l10n_pt_sale_downpayment/__init__.py
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+# Copyright (C) 2021 Open Source Integrators
+# License AGPL-3.0 or later (https://www.gnu.org/licenses/agpl).
+
+from . import models
diff --git a/l10n_pt_sale_downpayment/__manifest__.py b/l10n_pt_sale_downpayment/__manifest__.py
new file mode 100644
index 00000000..44212e56
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+++ b/l10n_pt_sale_downpayment/__manifest__.py
@@ -0,0 +1,21 @@
+# Copyright (C) 2021 Open Source Integrators
+# License AGPL-3.0 or later (https://www.gnu.org/licenses/agpl).
+
+{
+    "name": "Applied downpayments generate a Credit Note",
+    "summary": "Credit the original down payment invoice "
+    "and avoid negative invoice lines",
+    "version": "16.0.1.0.0",
+    "author": "Open Source Integrators, Odoo Community Association (OCA)",
+    "license": "AGPL-3",
+    "website": "https://github.com/OCA/l10n-portugal",
+    "category": "Accounting/Localizations/EDI",
+    "maintainers": ["dreispt"],
+    "development_status": "Beta",
+    "depends": ["sale"],
+    "data": [
+    ],
+    "images": ["static/description/cover.png"],
+    "application": True,
+    "installable": True,
+}
diff --git a/l10n_pt_sale_downpayment/models/__init__.py b/l10n_pt_sale_downpayment/models/__init__.py
new file mode 100644
index 00000000..399ff84b
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+++ b/l10n_pt_sale_downpayment/models/__init__.py
@@ -0,0 +1,4 @@
+# Copyright (C) 2023 Open Source Integrators
+# License AGPL-3.0 or later (https://www.gnu.org/licenses/agpl).
+
+from . import sale_order
diff --git a/l10n_pt_sale_downpayment/models/sale_order.py b/l10n_pt_sale_downpayment/models/sale_order.py
new file mode 100644
index 00000000..b761f23b
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+++ b/l10n_pt_sale_downpayment/models/sale_order.py
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+# Copyright (C) 2023 Open Source Integrators
+# License AGPL-3.0 or later (https://www.gnu.org/licenses/agpl).
+
+from odoo import _, api, exceptions, fields, models
+
+
+class SaleOrder(models.Model):
+    _inherit = "sale.order"
+
+    def _create_invoices(self, grouped=False, final=False, date=None):
+        moves = super()._create_invoices(grouped=grouped, final=final, date=date)
+        moves_downp = moves.filtered(lambda x: x.line_ids.filtered("is_downpayment"))
+        reverts = self.env["account.move"]
+        for move_dp in moves_downp:
+            revert_dp = move_dp.copy()
+            reverts |= revert_dp
+            move_lines_to_unlink = move_dp.invoice_line_ids.filtered(
+                lambda x: x.is_downpayment and x.price_subtotal < 0
+            )
+            move_lines_to_unlink.unlink()
+            revert_lines_to_unlink = revert_dp.invoice_line_ids.filtered(
+                lambda x: not (x.is_downpayment and x.price_subtotal < 0)
+            )
+            revert_lines_to_unlink.unlink()
+            # Keep link with Sale Order
+            so_lines = move_dp.invoice_line_ids.sale_line_ids
+            import pudb; pu.db
+            for line in revert_dp.invoice_line_ids:
+                line.sale_line_ids |= so_lines
+        return moves