In summer 2015, I travelled France and visited Neuf-Brisach (OK), Besancon (fantastic system of forts, most of them can be seen from the walls of main fort), Camaret-sur-Mer (small and rather poor WHS closed for maintainance 2015 but otherwise a very nice place to visit), Saint-Vaast-la-Hougne (unaccesable due to French military area), Arras (now completely opened, fort accessible by car and foot but no activity for tourists) and at last Longwy (worth a visit).

General lack of information in other languages than french, best i Besancon where they have found out about that.