diff --git a/odoo/addons/base/models/res_partner.py b/odoo/addons/base/models/res_partner.py
index c1cc1d04570..d6c13fc57d1 100644
--- a/odoo/addons/base/models/res_partner.py
+++ b/odoo/addons/base/models/res_partner.py
@@ -527,16 +527,17 @@ class Partner(models.Model):
             vals['website'] = self._clean_website(vals['website'])
         if vals.get('parent_id'):
             vals['company_name'] = False
-        if vals.get('company_id'):
-            company = self.env['res.company'].browse(vals['company_id'])
+        if 'company_id' in vals:
+            company_id = vals['company_id']
             for partner in self:
-                if partner.user_ids:
+                if company_id and partner.user_ids:
+                    company = self.env['res.company'].browse(company_id)
                     companies = set(user.company_id for user in partner.user_ids)
                     if len(companies) > 1 or company not in companies:
                         raise UserError(
                             ("The selected company is not compatible with the companies of the related user(s)"))
                 if partner.child_ids:
-                    partner.child_ids.write({'company_id': company.id})
+                    partner.child_ids.write({'company_id': company_id})
         result = True
         # To write in SUPERUSER on field is_company and avoid access rights problems.
         if 'is_company' in vals and self.user_has_groups('base.group_partner_manager') and not self.env.su:
diff --git a/odoo/addons/base/tests/test_res_partner.py b/odoo/addons/base/tests/test_res_partner.py
index 2a6722553af..743303ac100 100644
--- a/odoo/addons/base/tests/test_res_partner.py
+++ b/odoo/addons/base/tests/test_res_partner.py
@@ -2,6 +2,7 @@
 # Part of Odoo. See LICENSE file for full copyright and licensing details.
 
 from odoo.tests.common import TransactionCase
+from odoo.exceptions import UserError
 
 
 class TestPartner(TransactionCase):
@@ -17,3 +18,25 @@ class TestPartner(TransactionCase):
 
         ns_res = self.env['res.partner'].name_search('Vlad', args=[('user_ids.email', 'ilike', 'vlad')])
         self.assertEqual(set(i[0] for i in ns_res), set(test_user.partner_id.ids))
+
+    def test_company_change_propagation(self):
+        """ Check propagation of company_id across children """
+        User = self.env['res.users']
+        Partner = self.env['res.partner']
+        Company = self.env['res.company']
+
+        company_1 = Company.create({'name': 'company_1'})
+        company_2 = Company.create({'name': 'company_2'})
+
+        test_partner_company = Partner.create({'name': 'This company'})
+        test_user = User.create({'name': 'This user', 'login': 'thisu', 'email': 'this.user@example.com', 'company_id': company_1.id, 'company_ids': [company_1.id]})
+        test_user.partner_id.write({'parent_id': test_partner_company.id})
+
+        test_partner_company.write({'company_id': company_1.id})
+        self.assertEqual(test_user.partner_id.company_id.id, company_1.id, "The new company_id of the partner company should be propagated to its children")
+
+        test_partner_company.write({'company_id': False})
+        self.assertFalse(test_user.partner_id.company_id.id, "If the company_id is deleted from the partner company, it should be propagated to its children")
+
+        with self.assertRaises(UserError, msg="You should not be able to update the company_id of the partner company if the linked user of a child partner is not an allowed to be assigned to that company"), self.cr.savepoint():
+            test_partner_company.write({'company_id': company_2.id})