Since ancient times, its remarkable location has enabled simultaneous surveillance of the Hyères roadstead and a large area around the village, which it protects from Saracen incursions and brigandage on all sides. In 1531, while visiting Provence, King François 1er decided to consolidate the original structure and establish a garrison on the island of Porquerolles to protect the inhabitants and the Provencal coastline.

Behind 4-meter-thick walls, the tower houses a large 6-meter-high room, vaulted into a cupola with an oculus. It is topped by a terrace offering an exceptional view of the island and the Hyères roadstead.
The barracks house a permanent exhibition on the island's natural, cultural and historical heritage.

Since 2020, collaboration between the Parc national de Port-Cros and the Villa Carmignac has enabled the restoration of the tower, which houses an extension of the Villa Carmignac exhibition every year.

Take a virtual tour of Sainte-Agathe Fort:
https://360.adeo-web.fr/fort-sainte-agathe-2018/