In the Dordogne, between April 11th and May 3rd, as every year events are organized in over 100 castles. These include guided tours of castles not usually open to the public, shows, historical reenactments, concerts, games, and more.
Events calendar here: (sorry, in French only)
https://www.dordogne-perigord-tourisme.fr/chateaux-en-fete/toutes-les-animations-proposees/
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