diff --git a/README.md b/README.md
index 13a0575..da7d659 100644
--- a/README.md
+++ b/README.md
@@ -6,4 +6,5 @@ Addons for Odoo 18
 
 |  Name                  |  Version        |    Description                              |
 |------------------------|-----------------|---------------------------------------------|
-| gn_l10n_fr_pcg_asso    |  18.0.0.0.1     |  PCG pour les associations françaises       |
\ No newline at end of file
+| gn_l10n_fr_pcg_asso    |  18.0.0.0.1     |  PCG pour les associations françaises       |
+| gn_hr                  |  18.0.0.0.1     |  Module RH custom                           |
diff --git a/gn_hr/README.md b/gn_hr/README.md
new file mode 100644
index 0000000..012cfce
--- /dev/null
+++ b/gn_hr/README.md
@@ -0,0 +1,5 @@
+# GN HR
+
+This module allow to have overlapping contracts if they're expired.
+The current behavior forbids it unless contracts are in state "Draft" or "Cancel".
+We just modify method `_check_current_contract` on `hr.contract`.
diff --git a/gn_hr/__init__.py b/gn_hr/__init__.py
new file mode 100644
index 0000000..ca62191
--- /dev/null
+++ b/gn_hr/__init__.py
@@ -0,0 +1,2 @@
+# License LGPL-3.0 or later (http://www.gnu.org/licenses/lgpl).
+from . import models
\ No newline at end of file
diff --git a/gn_hr/__manifest__.py b/gn_hr/__manifest__.py
new file mode 100644
index 0000000..3553255
--- /dev/null
+++ b/gn_hr/__manifest__.py
@@ -0,0 +1,13 @@
+{
+    "name": "GN HR",
+    "version": "18.0.0.0.1",
+    "category": "HR",
+    "summary": "Custom HR module",
+    "author": "Le Garage Numérique",
+    "maintainers": ["makayabou"],
+    "website": "https://git.legaragenumerique.fr",
+    "depends": [
+        "hr_contract",
+    ],
+    "license": "LGPL-3",
+}
diff --git a/gn_hr/models/__init__.py b/gn_hr/models/__init__.py
new file mode 100644
index 0000000..b07b789
--- /dev/null
+++ b/gn_hr/models/__init__.py
@@ -0,0 +1 @@
+from . import hr_contract
diff --git a/gn_hr/models/hr_contract.py b/gn_hr/models/hr_contract.py
new file mode 100644
index 0000000..603e1a5
--- /dev/null
+++ b/gn_hr/models/hr_contract.py
@@ -0,0 +1,43 @@
+# -*- coding: utf-8 -*-
+
+from odoo import api, fields, models, _
+from odoo.exceptions import ValidationError
+
+from odoo.osv import expression
+
+import logging
+_logger = logging.getLogger(__name__)
+
+class Contract(models.Model):
+    _inherit = ['hr.contract']
+
+    @api.constrains('employee_id', 'state', 'kanban_state', 'date_start', 'date_end')
+    def _check_current_contract(self):
+        """ Two contracts in state [incoming | open | close] cannot overlap """
+        for contract in self.filtered(lambda c: (c.state not in ['draft', 'cancel', 'close'] or c.state == 'draft' and c.kanban_state == 'done') and c.employee_id):
+            domain = [
+                ('id', '!=', contract.id),
+                ('employee_id', '=', contract.employee_id.id),
+                ('company_id', '=', contract.company_id.id),
+                '|',
+                    ('state', 'in', ['open', 'close']),
+                    '&',
+                        ('state', '=', 'draft'),
+                        ('kanban_state', '=', 'done') # replaces incoming
+            ]
+
+            if not contract.date_end:
+                start_domain = []
+                end_domain = ['|', ('date_end', '>=', contract.date_start), ('date_end', '=', False)]
+            else:
+                start_domain = [('date_start', '<=', contract.date_end)]
+                end_domain = ['|', ('date_end', '>', contract.date_start), ('date_end', '=', False)]
+
+            domain = expression.AND([domain, start_domain, end_domain])
+            if self.search_count(domain):
+                raise ValidationError(
+                    _(
+                        'An employee can only have one contract at the same time. (Excluding Draft and Cancelled contracts).\n\nEmployee: %(employee_name)s',
+                        employee_name=contract.employee_id.name
+                    )
+                )