Yes, this is confirmed by aerial and street-level imageries where steel gates can be seen. Using street-level imagery the following sign can also be read : "Accès interdit à toute personne étrangère au service" which translates to "Access prohibited to any person external to the service". However there's somehow still quite a bit of people who manage to go through here according to the Strava Heatmap. Maybe visitors of the inclined plane?