diff --git a/odoo/addons/base/i18n/base.pot b/odoo/addons/base/i18n/base.pot
index a2eee7ba4ce..f867502b0a5 100644
--- a/odoo/addons/base/i18n/base.pot
+++ b/odoo/addons/base/i18n/base.pot
@@ -28591,6 +28591,12 @@ msgstr ""
 msgid "binary"
 msgstr ""
 
+#. module: base
+#: code:addons/base/models/ir_attachment.py:0
+#, python-format
+msgid "binary_field_real_user should be a res.users record."
+msgstr ""
+
 #. module: base
 #: model:ir.model.fields.selection,name:base.selection__ir_model_fields__ttype__boolean
 msgid "boolean"
diff --git a/odoo/addons/base/models/ir_attachment.py b/odoo/addons/base/models/ir_attachment.py
index 9190590cf29..e8421b143bf 100644
--- a/odoo/addons/base/models/ir_attachment.py
+++ b/odoo/addons/base/models/ir_attachment.py
@@ -341,6 +341,8 @@ class IrAttachment(models.Model):
                 'xml' in mimetype and    # other xml (svg, text/xml, etc)
                 not 'openxmlformats' in mimetype)  # exception for Office formats
         user = self.env.context.get('binary_field_real_user', self.env.user)
+        if not isinstance(user, self.pool['res.users']):
+            raise UserError(_("binary_field_real_user should be a res.users record."))
         force_text = xml_like and (
             self.env.context.get('attachments_mime_plainxml') or
             not self.env['ir.ui.view'].with_user(user).check_access_rights('write', False))