diff --git a/bda/models.py b/bda/models.py
index 5ef4f9bf..11c9dd3b 100644
--- a/bda/models.py
+++ b/bda/models.py
@@ -48,7 +48,7 @@ PAYMENT_TYPES = (
 )
 
 class Participant (models.Model):
-    user = models.ForeignKey(User, unique = True)
+    user = models.OneToOneField(User)
     choices = models.ManyToManyField(Spectacle, through = "ChoixSpectacle", related_name = "chosen_by")
     attributions = models.ManyToManyField(Spectacle, through = "Attribution", related_name = "attributed_to")
     paid = models.BooleanField (u"A payé", default = False)
diff --git a/bda2/models.py b/bda2/models.py
index bcc4e15c..c9fefe6e 100644
--- a/bda2/models.py
+++ b/bda2/models.py
@@ -48,7 +48,7 @@ PAYMENT_TYPES = (
 )
 
 class Participant (models.Model):
-    user = models.ForeignKey(User, unique = True, related_name = "participants2")
+    user = models.OneToOneField(User, related_name = "participants2")
     choices = models.ManyToManyField(Spectacle, through = "ChoixSpectacle", related_name = "chosen_by")
     attributions = models.ManyToManyField(Spectacle, through = "Attribution", related_name = "attributed_to")
     paid = models.BooleanField (u"A payé", default = False)
diff --git a/bda3/models.py b/bda3/models.py
index 80153233..6ada1be3 100644
--- a/bda3/models.py
+++ b/bda3/models.py
@@ -48,7 +48,7 @@ PAYMENT_TYPES = (
 )
 
 class Participant (models.Model):
-    user = models.ForeignKey(User, unique = True, related_name = "participants3")
+    user = models.OneToOneField(User, related_name = "participants3")
     choices = models.ManyToManyField(Spectacle, through = "ChoixSpectacle", related_name = "chosen_by")
     attributions = models.ManyToManyField(Spectacle, through = "Attribution", related_name = "attributed_to")
     paid = models.BooleanField (u"A payé", default = False)