The Tower can be visited
Donjon Beaugency

In the French region of Centre-Val de Loire stands the Donjon Beaugency, a residential tower from the 11th century. It is one of the few largely preserved examples of its kind in France.
History+
The origins of the keep date back to the 11th century. The rectangular fortress, also known as Tour de César, was originally about 36 meters high and surrounded by an earth embankment up to six meters high for defensive purposes. A double curtain wall provided protection. In the 13th or 14th century, two floors were added to the tower.
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: 47.7773, 1.6331