diff --git a/event/models.py b/event/models.py
index 064d33f..a93ea3a 100644
--- a/event/models.py
+++ b/event/models.py
@@ -1,5 +1,6 @@
 from django.contrib.auth.models import User
 from django.utils.translation import ugettext_lazy as _
+from django.core.validators import RegexValidator
 from django.core import exceptions
 from django.db import models
 from re import search as re_search
@@ -72,10 +73,16 @@ class ActivityTag(models.Model):
     is_public = models.BooleanField(
                     help_text=_("TODO"),
                 )
+    color_regex = RegexValidator(
+                regex=r'^#(?:[0-9a-fA-F]{3}){1,2}$',
+                message="La chaîne de caractère rentrée n'est pas"
+                "une couleur en hexadécimal.",
+                )
     color = models.CharField(
                     _('Couleur'),
                     max_length=7,
-                    validators=[validate_color],
+                    validators=[color_regex],
+                    help_text="Rentrer une couleur en hexadécimal",
                 )
 
     class Meta: