diff --git a/passerelle/apps/vivaticket/models.py b/passerelle/apps/vivaticket/models.py
index e9ce0ba4..9cb66855 100644
--- a/passerelle/apps/vivaticket/models.py
+++ b/passerelle/apps/vivaticket/models.py
@@ -111,10 +111,7 @@ EVENTBOOK_SCHEMA = {
             "description": "room id",
             "type": "string",
         },
-        "quantity": {
-            "description": "quantity",
-            "type": "integer",
-        },
+        "quantity": {"description": "quantity", "type": "string", "pattern": "^[0-9]+$"},
         "booking_comment": {
             "description": "booking comment",
             "type": "string",
@@ -279,7 +276,7 @@ class VivaTicket(BaseResource):
                     'eventCategoryCode': post_data['event'],
                     'roomCode': post_data['room'],
                     'themeCode': post_data['theme'],
-                    'quantity': post_data['quantity'],
+                    'quantity': int(post_data['quantity']),
                     'startDateTime': post_data['start_datetime'],
                     'endDateTime': post_data['end_datetime'],
                     'comment': post_data.get('room_comment', ''),
diff --git a/tests/test_vivaticket.py b/tests/test_vivaticket.py
index 540c7d21..1091984a 100644
--- a/tests/test_vivaticket.py
+++ b/tests/test_vivaticket.py
@@ -355,7 +355,7 @@ def test_book(mocked_get, mocked_put, mocked_post, app, connector):
     payload['theme'] = '001'
     payload['room'] = 'v001'
     payload['school_level'] = '01'
-    payload['quantity'] = 1
+    payload['quantity'] = '01'
     payload['booking_comment'] = 'Booking comment'
     payload['room_comment'] = 'Room comment'
     payload['form_url'] = "http://mysite.com/form/id/"
@@ -376,6 +376,7 @@ def test_book(mocked_get, mocked_put, mocked_post, app, connector):
     assert mocked_post.call_args[1]['json']['Booking']['endDateTime'] == '2019-01-15T11:00'
     assert mocked_post.call_args[1]['json']['Booking']['comment'] == 'Booking comment'
     assert mocked_post.call_args[1]['json']['Booking']['roomList'][0]['comment'] == 'Room comment'
+    assert mocked_post.call_args[1]['json']['Booking']['roomList'][0]['quantity'] == 1
     assert mocked_post.call_args[1]['json']['Booking']['roomList'][0]['schoolLevelCode'] == '01'
     assert mocked_post.call_args[1]['json']['Booking']['contact'] == {'InternalCode': '0000000273'}
     assert mocked_post.call_args[1]['headers'] == {'X-Vivaticket-Form-URL': 'http://mysite.com/form/id/'}