The Château de Vincennes must be in the running for the most stupendously underrated tourist attraction in the Paris area. It’s located right in the middle of a pleasantly dense suburban street where you have to stop a moment to take in the unreality that this was in fact the residence of the French royal family before it decamped for the much more palatial Versailles. You just walk out of the train station and there it is: a castle with a keep of dazzling scale and height. In a way it’s misleading to underscore the suburban milieu, because the château was built as a royal hunting lodge long before the current town around it developed in any substantial way. Used variously over time as a home, as a fortress and as a prison (for the Marquis de Sade and Diderot, among others), it dates from a time when the royal family needed defenses, yet it’s stylish withal. Oh, and forget those Versailles-type lines that you have to plan your whole week around. At Vincennes you walk right in. Depending on when you go, you may even get the feeling that you have the whole castle to yourself.