The Fort can be visited
Barrière de l’Esseillon-Fort Victor-Emmanuel

In the municipality of Aussois in the French region of Auvergne-Rhône-Alpes is Fort Victor-Emmanuel. It is the largest component of the former Barrière de l’Esseillon defense line and an example of 19th-century military architecture.
History+
Fort Victor-Emmanuel was built as part of the Barrière de l’Esseillon, a defensive line constructed between 1819 and 1834. Its construction was made possible by reparations paid by France to the Kingdom of Sardinia after the Congress of Vienna. The aim was to protect the Duchy of Savoy and access to Mont Cenis, as Savoy was then part of the Kingdom of Sardinia and served as a buffer zone to France. Named after members of the House of Savoy, Fort Victor-Emmanuel was the largest of the five forts and could accommodate a garrison of up to 1500 men. Although the installations were never involved in direct combat, the Barrière played a role.
Source: Wikipedia · Licence: CC BY-SA 4.0 · Image: Christa1004
This description draws on the facts documented in the linked Wikipedia article; Wikipedia content is licensed under CC BY-SA 4.0. Wording and editing: Mobile History.
Location: 45.2118, 6.7362