The only guided access to the abbey runs on Saturday afternoons between May and October. Outside that window you can drive past, photograph the outer walls, and visit Ville-sous-la-Ferté, but you cannot get inside. Book your tour at least a few weeks in advance, especially in July and August when the slots fill quickly.
Spring and early autumn are the best times: the Aube valley is at its greenest in May and June, while the surrounding forests turn dramatically in October. Winter visits are possible to the area but offer no abbey access.