diff --git a/addons/project/models/project.py b/addons/project/models/project.py
index af136d9f227..bbf961f4c2c 100644
--- a/addons/project/models/project.py
+++ b/addons/project/models/project.py
@@ -313,7 +313,7 @@ class Project(models.Model):
     active = fields.Boolean(default=True,
         help="If the active field is set to False, it will allow you to hide the project without removing it.")
     sequence = fields.Integer(default=10)
-    partner_id = fields.Many2one('res.partner', string='Customer', auto_join=True, tracking=True, domain="['|', ('company_id', '=', False), ('company_id', '=', company_id)]")
+    partner_id = fields.Many2one('res.partner', string='Customer', auto_join=True, tracking=True, check_company=True)
     partner_email = fields.Char(
         compute='_compute_partner_email', inverse='_inverse_partner_email',
         string='Email', readonly=False, store=True, copy=False)
diff --git a/addons/project/models/res_partner.py b/addons/project/models/res_partner.py
index 26998e10827..0259842c659 100644
--- a/addons/project/models/res_partner.py
+++ b/addons/project/models/res_partner.py
@@ -8,7 +8,9 @@ from odoo.tools import email_normalize
 class ResPartner(models.Model):
     """ Inherits partner and adds Tasks information in the partner form """
     _inherit = 'res.partner'
+    _check_company_auto = True
 
+    project_ids = fields.One2many('project.project', 'partner_id', string='Projects', check_company=True)
     task_ids = fields.One2many('project.task', 'partner_id', string='Tasks')
     task_count = fields.Integer(compute='_compute_task_count', string='# Tasks')
 
diff --git a/addons/project/tests/test_project_base.py b/addons/project/tests/test_project_base.py
index ad7f82b8b01..7c7c8027d1a 100644
--- a/addons/project/tests/test_project_base.py
+++ b/addons/project/tests/test_project_base.py
@@ -174,3 +174,26 @@ class TestProjectBase(TestProjectCommon):
 
         self.assertTrue(self.project_pigs.id < self.project_goats.id)
         self.assertEqual(Project.search(domain, order='id').ids, project_ids)
+
+    def test_change_project_or_partner_company(self):
+        """ Tests that it is impossible to change the company of a project
+            if the company of the partner is different and vice versa.
+        """
+        company_1 = self.env.company
+        company_2 = self.env['res.company'].create({'name': 'Company 2'})
+        partner = self.env['res.partner'].create({
+            'name': 'Partner',
+        })
+        self.project_pigs.partner_id = partner
+        # Can change the company of a project if the company of the partner is not set
+        self.assertFalse(partner.company_id)
+        self.project_pigs.company_id = company_2
+        self.project_pigs.partner_id.company_id = company_2
+
+        with self.assertRaises(UserError):
+            # Cannot change the company of a partner if the company of the project is different
+            partner.company_id = company_1
+
+        with self.assertRaises(UserError):
+            # Cannot change the company of a project if the company of the partner is different
+            self.project_pigs.company_id = company_1