The Castle can be visited
Château de Niort

In the French town of Niort in the Deux-Sèvres department of the Nouvelle-Aquitaine region stands the Château de Niort. It shapes the cityscape with its twin towers overlooking the Sèvre Niortaise valley.
History+
The origins of the current castle complex date back to Henry II Plantagenet, who began its construction, and it was completed by Richard the Lionheart. Located on the Sèvre Niortaise, it served as a base for the English Crown. In the 15th century, the area between the two square towers was roofed over and converted into living quarters. The castle suffered damage during the Wars of Religion. From the 18th century, the Château de Niort was used as a prison. In 1840, the complex was classified as a Monument historique and later housed various functions before finding its current purpose as a museum.
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: 46.3253, -0.4651