diff --git a/users/migrations/0055_auto_20171003_0556.py b/users/migrations/0055_auto_20171003_0556.py
new file mode 100644
index 00000000..84d901c8
--- /dev/null
+++ b/users/migrations/0055_auto_20171003_0556.py
@@ -0,0 +1,21 @@
+# -*- coding: utf-8 -*-
+# Generated by Django 1.10.7 on 2017-10-03 03:56
+from __future__ import unicode_literals
+
+import django.core.validators
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('users', '0054_auto_20170626_2219'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='listright',
+            name='listright',
+            field=models.CharField(max_length=255, unique=True, validators=[django.core.validators.RegexValidator('^[a-z]+$', message='Les groupes unix ne peuvent contenir que des lettres minuscules')]),
+        ),
+    ]
diff --git a/users/models.py b/users/models.py
index 652d2e1d..22364a49 100644
--- a/users/models.py
+++ b/users/models.py
@@ -48,6 +48,7 @@ from django.utils import timezone
 from django.contrib.auth.models import AbstractBaseUser, BaseUserManager
 
 from django.core.validators import MinLengthValidator
+from django.core.validators import RegexValidator
 from topologie.models import Room
 from cotisations.models import Cotisation, Facture, Paiement, Vente
 from machines.models import Domain, Interface, MachineType, Machine, Nas, MachineType, Extension, regen
@@ -619,7 +620,7 @@ class School(models.Model):
 class ListRight(models.Model):
     PRETTY_NAME = "Liste des droits existants"
 
-    listright = models.CharField(max_length=255, unique=True)
+    listright = models.CharField(max_length=255, unique=True, validators=[RegexValidator('^[a-z]+$', message="Les groupes unix ne peuvent contenir que des lettres minuscules")])
     gid = models.IntegerField(unique=True, null=True)
     details = models.CharField(help_text="Description", max_length=255, blank=True)