The Fortress can be visited
Citadelle de Mane

The citadel of Mane is a citadel located in the commune of Mane, near Forcalquier in the Alpes-de-Haute-Provence in France. A private property, the citadel of Mane is also sometimes called the castle of Mane.
Architecture+
It is the only fortification still intact in all of Haute Provence. The strategic interest of this castle is explained by Mane's position at the gates of Forcalquier, the capital of the county. It is defended by a double helical enclosure that surrounds the hill overlooking Mane. It includes a dwelling with mullioned windows.
History+
The citadel of Mane owes its construction to the Counts of Toulouse in the 12th century. The oldest parts are attributable to Guillaume II, Count of Forcalquier. Around 1250, it was sold to Charles I of Anjou (brother of Saint Louis) and husband of Beatrice of Provence (daughter of Raymond Béranger V).
Source: Wikipedia · Licence: CC BY-SA 4.0 · Image: Hervé Rebours
This description draws on the facts documented in the linked Wikipedia article; Wikipedia content is licensed under CC BY-SA 4.0. Wording and editing: Mobile History.
Location: 43.9382, 5.7684