Hi Frédéric,
You must need to configure MVC project with this
Configurations
1.install the Kentico.Web.Mvc integration package in your MVC application project.
2.In the MVC application's Global.asax file, add a reference to Kentico.Web.Mvc.
3.In the Views\web.config file, add the Kentico.Web.Mvc namespace.
How to use-asp-net-mvc-with-kentico-cms