diff --git a/equipment/models.py b/equipment/models.py
index 84dd205..6498756 100644
--- a/equipment/models.py
+++ b/equipment/models.py
@@ -1,7 +1,7 @@
 from django.db import models
+from django.core.exceptions import ValidationError
 from django.utils.translation import ugettext_lazy as _
-from event.models import Activity
-from shared.models import EventSpecificMixin
+from event.models import Activity, EventSpecificMixin
 
 
 class Equipment(EventSpecificMixin, models.Model):
@@ -18,8 +18,8 @@ class Equipment(EventSpecificMixin, models.Model):
             )
 
     class Meta:
-        verbose_name = _("matériel permanent")
-        verbose_name_plural = _("matériels permanents")
+        verbose_name = _("matériel")
+        verbose_name_plural = _("matériels")
 
     def __str__(self):
         return self.name
@@ -40,6 +40,12 @@ class EquipmentAttribution(models.Model):
                                   self.amout,
                                   self.activity.get_herited('title'))
 
+    def save(self, *args, **kwargs):
+        if self.equipment.event and self.equipment.event != self.activity.event:
+            raise ValidationError
+
+        super(EquipmentAttribution, self).save(*args, **kwargs)
+
 
 class EquipmentRemark(models.Model):
     remark = models.TextField(_("remarque sur le matériel"))
diff --git a/event/models.py b/event/models.py
index fca94c2..14d7980 100644
--- a/event/models.py
+++ b/event/models.py
@@ -4,7 +4,6 @@ from django.core.validators import RegexValidator
 from django.core.exceptions import FieldError
 from django.db import models
 from communication.models import SubscriptionMixin
-from shared.models import EventSpecificMixin
 
 
 class Event(SubscriptionMixin, models.Model):
@@ -39,6 +38,23 @@ class Event(SubscriptionMixin, models.Model):
         return self.title
 
 
+class EventSpecificMixin(models.Model):
+    """Mixin allowing for event-specific models instances
+    or not (depending on whether the event field is null)"""
+
+    event = models.ForeignKey(
+        'event.Event',
+        verbose_name=_("évènement"),
+        help_text=_("Si spécifié, l'instance du modèle "
+                    "est spécifique à l'évènement en question"),
+        blank=True,
+        null=True
+    )
+
+    class Meta:
+        abstract = True
+
+
 class Place(EventSpecificMixin, models.Model):
     name = models.CharField(
                     _("nom du lieu"),