diff --git a/hr_effective_attendance_period/README.rst b/hr_effective_attendance_period/README.rst
new file mode 100644
index 0000000..b8c44b5
--- /dev/null
+++ b/hr_effective_attendance_period/README.rst
@@ -0,0 +1,43 @@
+==============================
+hr_effective_attendance_period
+==============================
+
+Provide indication that attendance are effectively worked periods or not
+
+Installation
+============
+
+Use Odoo normal module installation procedure to install
+``hr_effective_attendance_period``.
+
+Known issues / Roadmap
+======================
+
+None yet.
+Bug Tracker
+===========
+
+Bugs are tracked on `our issues website <https://github.com/elabore-coop/hr-tools/issues>`_. In case of
+trouble, please check there if your issue has already been
+reported. If you spotted it first, help us smashing it by providing a
+detailed and welcomed feedback.
+
+Credits
+=======
+
+Contributors
+------------
+
+* Stéphan Sainléger
+
+Funders
+-------
+
+The development of this module has been financially supported by:
+* Elabore (https://elabore.coop)
+
+
+Maintainer
+----------
+
+This module is maintained by Elabore.
diff --git a/hr_effective_attendance_period/__init__.py b/hr_effective_attendance_period/__init__.py
new file mode 100644
index 0000000..cde864b
--- /dev/null
+++ b/hr_effective_attendance_period/__init__.py
@@ -0,0 +1,3 @@
+# -*- coding: utf-8 -*-
+
+from . import models
diff --git a/hr_effective_attendance_period/__manifest__.py b/hr_effective_attendance_period/__manifest__.py
new file mode 100644
index 0000000..7a7877a
--- /dev/null
+++ b/hr_effective_attendance_period/__manifest__.py
@@ -0,0 +1,37 @@
+# Copyright 2023 Stéphan Sainléger (Elabore)
+# License AGPL-3.0 or later (http://www.gnu.org/licenses/agpl).
+
+{
+    "name": "hr_effective_attendance_period",
+    "version": "14.0.1.0.0",
+    "author": "Elabore",
+    "website": "https://elabore.coop",
+    "maintainer": "Stéphan Sainléger",
+    "license": "AGPL-3",
+    "category": "Tools",
+    "summary": "Provide indication that attendance are effectively worked periods or not",
+    # any module necessary for this one to work correctly
+    "depends": [
+        "base",
+        "resource",
+    ],
+    "qweb": [
+        # "static/src/xml/*.xml",
+    ],
+    "external_dependencies": {
+        "python": [],
+    },
+    # always loaded
+    "data": [
+        "views/resource_views.xml",
+    ],
+    # only loaded in demonstration mode
+    "demo": [],
+    "js": [],
+    "css": [],
+    "installable": True,
+    # Install this module automatically if all dependency have been previously
+    # and independently installed.  Used for synergetic or glue modules.
+    "auto_install": False,
+    "application": False,
+}
\ No newline at end of file
diff --git a/hr_effective_attendance_period/i18n/README b/hr_effective_attendance_period/i18n/README
new file mode 100644
index 0000000..62197a1
--- /dev/null
+++ b/hr_effective_attendance_period/i18n/README
@@ -0,0 +1 @@
+This directory should contain the *.po for Odoo translation.
diff --git a/hr_effective_attendance_period/models/__init__.py b/hr_effective_attendance_period/models/__init__.py
new file mode 100644
index 0000000..d0ad81e
--- /dev/null
+++ b/hr_effective_attendance_period/models/__init__.py
@@ -0,0 +1 @@
+from . import resource
\ No newline at end of file
diff --git a/hr_effective_attendance_period/models/resource.py b/hr_effective_attendance_period/models/resource.py
new file mode 100644
index 0000000..5f6af34
--- /dev/null
+++ b/hr_effective_attendance_period/models/resource.py
@@ -0,0 +1,7 @@
+from odoo import models, fields
+
+
+class ResourceCalendarAttendance(models.Model):
+    _inherit = "resource.calendar.attendance"
+
+    effective_attendance_period = fields.Boolean('Effective Attendance Period', store=True)
\ No newline at end of file
diff --git a/hr_effective_attendance_period/views/resource_views.xml b/hr_effective_attendance_period/views/resource_views.xml
new file mode 100644
index 0000000..b3a3226
--- /dev/null
+++ b/hr_effective_attendance_period/views/resource_views.xml
@@ -0,0 +1,26 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<odoo>
+    <record id="view_resource_calendar_attendance_tree_inherit_effective_attendance"
+        model="ir.ui.view">
+        <field name="name">resource.calendar.attendance.view.tree.inherit</field>
+        <field name="model">resource.calendar.attendance</field>
+        <field name="inherit_id" ref="resource.view_resource_calendar_attendance_tree" />
+        <field name="arch" type="xml">
+            <xpath expr="//field[@name='week_type']" position="after">
+                <field name="effective_attendance_period" />
+            </xpath>
+        </field>
+    </record>
+
+    <record id="view_resource_calendar_attendance_form_inherit_effective_attendance"
+        model="ir.ui.view">
+        <field name="name">resource.calendar.attendance.view.tree.inherit</field>
+        <field name="model">resource.calendar.attendance</field>
+        <field name="inherit_id" ref="resource.view_resource_calendar_attendance_form" />
+        <field name="arch" type="xml">
+            <xpath expr="//field[@name='day_period']" position="after">
+                <field name="effective_attendance_period" />
+            </xpath>
+        </field>
+    </record>
+</odoo>
\ No newline at end of file