Fort Saint-Sébastien

Fort Saint-Sébastien is a military training fort in Saint-Germain-en-Laye that spans about 32 hectares with earthwork fortifications and wooden structures. The site displays a sophisticated system of trenches and training areas for combat exercises.

The fort was built in 1669 under Louis XIV and served as a training ground for up to 20,000 soldiers and several thousand horses. The project followed modern fortification techniques and shaped French military training of the era.

The fort reflects French military engineering ideals through its network of zigzag trenches designed for defense practice. Visitors can see how soldiers trained their tactical skills in this organized layout.

The grounds are open to visitors today, and archaeological excavations between 2011 and 2012 revealed the fort's structures, including defensive trenches and training areas. You can explore the remains of the historical installations on site.

The fort employed revolutionary siege techniques that later contributed to France's swift victory at Maastricht in 1673. These innovative methods made the site a key location for developing modern military tactics.