diff --git a/cotisations/migrations/0040_auto_20180705_0822.py b/cotisations/migrations/0040_auto_20180705_0822.py
new file mode 100644
index 00000000..31b0652a
--- /dev/null
+++ b/cotisations/migrations/0040_auto_20180705_0822.py
@@ -0,0 +1,20 @@
+# -*- coding: utf-8 -*-
+# Generated by Django 1.10.7 on 2018-07-05 13:22
+from __future__ import unicode_literals
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('cotisations', '0039_auto_20180704_1147'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='balancepayment',
+            name='minimum_balance',
+            field=models.DecimalField(decimal_places=2, default=0, help_text='The minimal amount of money allowed for the balance at the end of a payment. You can specify negative amount.', max_digits=5, verbose_name='Minimum balance'),
+        ),
+    ]
diff --git a/cotisations/payment_methods/balance/models.py b/cotisations/payment_methods/balance/models.py
index ae4d2f0b..164136b9 100644
--- a/cotisations/payment_methods/balance/models.py
+++ b/cotisations/payment_methods/balance/models.py
@@ -27,6 +27,7 @@ class BalancePayment(PaymentMethodMixin, models.Model):
                      ),
         max_digits=5,
         decimal_places=2,
+        default=0,
     )
     maximum_balance = models.DecimalField(
         verbose_name=_l("Maximum balance"),