Richelieu had unused forts filled with gunpowder and blown up. I suppose it was the most efficient way to get the stones back to build other stuff.
The Regneville castle partially survived the ordeal...
https://www.google.com/maps/place/Ch%C3%A2teau+De+Regn%C3%A9...
https://www.google.com/maps/place/Ch%C3%A2teau+De+Regn%C3%A9...