There was an inviting "Coquille Saint-Jacques", but I read as well the "Propriété Privée" and learned from another sign, that guided tours were possible "sur rendez-vous"... I had no appointment, as I was just passing by - and so did not enter the premises.

This was obviously the residency of the medieval archpriest, representing the bishop. I walked all around the fence as a small Romanesque church is part of the ensemble. Here is the chapel´s portal.