The UNESCO Vauban list has a French language Historical Description for each site. This is my translation of the description for Villefranche
Closing a crossing point, the urban enceinte was profoundly amended by Vauban in 1669. The fort of Villefranche, renamed LIbéria in the 20th century, was constructed after 1679. The three bastions were added in the 19th century. The underground staircase dates to 1850 - 56. The fort is private property, having been sold in 1927, it is open to the public. La Cova Vastera was built in 1707, after the death of Vauban. Sold in 1727, it was converted to a museum of the dinosaurs. At the end of the 1990's, Villefranche was receiving 500,000 visitors annually.