In the Middle Ages, the tower was crowned with machicolations from which the watchmen could monitor all possible access to the valley (Col Bas, Bernardez, Pierre, Maure, Charcherie, Fanget or Bayons combe). Col. Saint Jean was visible only in the castles of Selonnet and Montclar, which were communicated by signals.
Once included in the citadel, the tower continues to fulfill its monitoring function, serving as a "rider" at the north entrance to the Fort. It was also used as a store.
To allow visitors to enjoy the panoramic view from the top of the tower, the Historic Monuments Services have chosen not to restore the walls on the south and east sides of the terrace.
The north side suggests you the state of the tower in the 17th century.
The slate roof added in the 19th century has not been restored.