The Fort can be visited
Barrière de l’Esseillon-Redoute Marie-Thérèse

The Redoute Marie-Thérèse, a component of the former Barrière de l’Esseillon defense line, is located in the municipality of Aussois in the Auvergne-Rhône-Alpes region of France, at approximately 1245 meters above sea level. It is a structure of early 19th-century military architecture, distinguished by its strategic position on the left bank of the Arc River.
History+
The Barrière de l’Esseillon, which includes the Redoute Marie-Thérèse, was constructed between 1819 and 1834. Its construction was made possible by reparations paid by France to the Kingdom of Sardinia following the Congress of Vienna. The objective was to protect Savoy, then part of the Kingdom of Sardinia, and secure access to Mont Cenis.
Image: http://commons.wikimedia.org/wiki/File:Redoute_Marie-Th%C3%A9r%C3%A8se.jpg
Location: 45.2083, 6.7356