diff --git a/addons/website_sale_digital/controllers/main.py b/addons/website_sale_digital/controllers/main.py
index c9708912a67..3a5b1434ddb 100644
--- a/addons/website_sale_digital/controllers/main.py
+++ b/addons/website_sale_digital/controllers/main.py
@@ -3,6 +3,8 @@
 
 import base64
 import io
+import os
+import mimetypes
 from werkzeug.utils import redirect
 
 from odoo import http
@@ -71,7 +73,7 @@ class WebsiteSaleDigital(CustomerPortal):
         # Check if this is a valid attachment id
         attachment = request.env['ir.attachment'].sudo().search_read(
             [('id', '=', int(attachment_id))],
-            ["name", "datas", "file_type", "res_model", "res_id", "type", "url"]
+            ["name", "datas", "datas_fname", "mimetype", "res_model", "res_id", "type", "url"]
         )
 
         if attachment:
@@ -105,6 +107,11 @@ class WebsiteSaleDigital(CustomerPortal):
                 return request.not_found()
         elif attachment["datas"]:
             data = io.BytesIO(base64.standard_b64decode(attachment["datas"]))
-            return http.send_file(data, filename=attachment['name'], as_attachment=True)
+            # we follow what is done in ir_http's binary_content for the extension management
+            extension = os.path.splitext(attachment["datas_fname"] or '')[1]
+            extension = extension if extension else mimetypes.guess_extension(attachment["mimetype"] or '')
+            filename = attachment['name']
+            filename = filename if os.path.splitext(filename)[1] else filename + extension
+            return http.send_file(data, filename=filename, as_attachment=True)
         else:
             return request.not_found()