diff --git a/addons/crm/tests/common.py b/addons/crm/tests/common.py
index 23babc0843d..c50e44c1593 100644
--- a/addons/crm/tests/common.py
+++ b/addons/crm/tests/common.py
@@ -296,6 +296,13 @@ class TestCrmCommon(TestSalesCommon, MailCase):
             'user_id': cls.user_sales_manager.id,
         })
 
+        cls.partner_c2 = cls.env['res.partner'].create({
+            'company_id': cls.company_2.id,
+            'email': '"Partner C2" <partner_c2@multicompany.example.com>',
+            'name': 'Customer for C2',
+            'phone': '+32455001122',
+        })
+
     def _create_leads_batch(self, lead_type='lead', count=10, email_dup_count=0,
                             partner_count=0, partner_ids=None, user_ids=None,
                             country_ids=None, probabilities=None, suffix=''):
diff --git a/addons/crm/tests/test_crm_lead_multicompany.py b/addons/crm/tests/test_crm_lead_multicompany.py
index 1b5bebc71dd..9cdab1aa562 100644
--- a/addons/crm/tests/test_crm_lead_multicompany.py
+++ b/addons/crm/tests/test_crm_lead_multicompany.py
@@ -2,7 +2,7 @@
 # Part of Odoo. See LICENSE file for full copyright and licensing details.
 
 from odoo.addons.crm.tests.common import TestCrmCommon
-from odoo.exceptions import AccessError
+from odoo.exceptions import AccessError, UserError
 from odoo.tests import Form, tagged
 from odoo.tests.common import users
 
@@ -116,6 +116,38 @@ class TestCRMLeadMultiCompany(TestCrmCommon):
         self.assertEqual(lead.team_id, self.sales_team_1)
         self.assertEqual(lead.user_id, self.user_sales_manager_mc)
 
+
+    @users('user_sales_manager_mc')
+    def test_lead_mc_company_computation_partner_restrict(self):
+        """ Check company on partner limits the company on lead. As contacts may
+        be separated by company, lead with a partner should be limited to that
+        company. """
+        partner_c2 = self.partner_c2.with_env(self.env)
+        self.assertEqual(partner_c2.company_id, self.company_2)
+        lead = self.env['crm.lead'].create({
+            'partner_id': partner_c2.id,
+            'name': 'MC Partner, no company lead',
+            'user_id': False,
+            'team_id': False,
+        })
+        self.assertEqual(lead.company_id, self.company_2)
+
+        partner_main = self.env['res.partner'].create({
+            'company_id': self.company_main.id,
+            'email': 'partner_main@multicompany.example.com',
+            'name': 'Customer for Main',
+        })
+        lead.write({'partner_id': partner_main})
+        self.assertEqual(lead.company_id, self.company_main)
+
+        # writing current user on lead would imply putting its team and team's company
+        # on lead (aka self.company_2), and this clashes with company restriction on
+        # customer
+        with self.assertRaises(UserError):
+            lead.write({
+                'user_id': self.env.user,
+            })
+
     @users('user_sales_manager_mc')
     def test_lead_mc_company_form(self):
         """ Test lead company computation using form view """
@@ -187,3 +219,21 @@ class TestCRMLeadMultiCompany(TestCrmCommon):
         crm_lead_form.user_id = self.env.user
         # self.assertEqual(crm_lead_form.company_id, self.env['res.company'])  # FIXME
         self.assertEqual(crm_lead_form.company_id, self.company_2)
+
+    @users('user_sales_manager_mc')
+    def test_lead_mc_company_form_w_partner_id(self):
+        """ Test lead company computation with partner having a company. """
+        partner_c2 = self.partner_c2.with_env(self.env)
+        crm_lead_form = Form(self.env['crm.lead'])
+        crm_lead_form.name = "Test Lead"
+
+        crm_lead_form.user_id = self.user_sales_manager_mc
+        crm_lead_form.partner_id = partner_c2
+        self.assertEqual(crm_lead_form.company_id, self.company_2, 'Crm: company comes from sales')
+        self.assertEqual(crm_lead_form.team_id, self.team_company2, 'Crm: team comes from sales')
+
+        # reset sales: should not reset company, as partner constrains it
+        crm_lead_form.team_id = self.env['crm.team']
+        crm_lead_form.user_id = self.env['res.users']
+        # ensuring that company_id is not overwritten when the salesperson becomes empty (w\o any team_id)
+        self.assertEqual(crm_lead_form.company_id, self.company_2, 'Crm: company comes from partner')