diff --git a/manuels/migrations/0023_auto_20180604_1827.py b/manuels/migrations/0023_auto_20180604_1827.py
new file mode 100644
index 0000000..3b4f141
--- /dev/null
+++ b/manuels/migrations/0023_auto_20180604_1827.py
@@ -0,0 +1,19 @@
+# Generated by Django 2.0.5 on 2018-06-04 16:27
+
+from django.db import migrations, models
+import manuels.models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('manuels', '0022_teacher_has_confirmed_list'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='book',
+            name='price',
+            field=models.FloatField(validators=[manuels.models.positive_float_validator], verbose_name='prix'),
+        ),
+    ]
diff --git a/manuels/models.py b/manuels/models.py
index 7b2acb7..c5380d8 100644
--- a/manuels/models.py
+++ b/manuels/models.py
@@ -131,6 +131,17 @@ def isbn_validator(value):
         raise ValidationError("%(value)s n'est pas un ISBN valide.", params={'value': value})
 
 
+def positive_float_validator(value):
+    try:
+        value = float(value)
+    except ValueError:
+        raise ValidationError("%(value)s doit être un nombre décimal")
+
+    if value < 0:
+        raise ValidationError("%(value)s doit être un nombre positif")
+
+
+
 class Book(BaseModel):
     class Meta:
         verbose_name = 'livre'
@@ -150,7 +161,7 @@ class Book(BaseModel):
                   "suivis de la lettre <code>X</code>",
         validators=[isbn_validator]
     )
-    price = models.PositiveIntegerField('prix')
+    price = models.FloatField('prix', validators=[positive_float_validator])
     YES_NO_CHOICE = (
         (False, 'Non'),
         (True, 'Oui'),