diff --git a/cotisations/migrations/0017_auto_20170718_2329.py b/cotisations/migrations/0017_auto_20170718_2329.py
new file mode 100644
index 00000000..4980bb1e
--- /dev/null
+++ b/cotisations/migrations/0017_auto_20170718_2329.py
@@ -0,0 +1,26 @@
+# -*- coding: utf-8 -*-
+# Generated by Django 1.10.7 on 2017-07-18 21:29
+from __future__ import unicode_literals
+
+import django.core.validators
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('cotisations', '0016_auto_20160715_0110'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='article',
+            name='duration',
+            field=models.IntegerField(blank=True, help_text='Durée exprimée en mois entiers', null=True, validators=[django.core.validators.MinValueValidator(0)]),
+        ),
+        migrations.AlterField(
+            model_name='article',
+            name='name',
+            field=models.CharField(max_length=255, unique=True),
+        ),
+    ]
diff --git a/cotisations/models.py b/cotisations/models.py
index 63cf97e2..45e9308d 100644
--- a/cotisations/models.py
+++ b/cotisations/models.py
@@ -104,10 +104,10 @@ def vente_post_delete(sender, **kwargs):
 class Article(models.Model):
     PRETTY_NAME = "Articles en vente"
 
-    name = models.CharField(max_length=255)
+    name = models.CharField(max_length=255, unique=True)
     prix = models.DecimalField(max_digits=5, decimal_places=2)
     iscotisation = models.BooleanField()
-    duration = models.IntegerField(help_text="Durée exprimée en mois entiers", blank=True, null=True)
+    duration = models.IntegerField(validators=[MinValueValidator(0)], help_text="Durée exprimée en mois entiers", blank=True, null=True)
 
 
     def clean(self):