Paris

Château de Vincennes and Chapelle
The Château de Vincennes is a massive 14th and 17th century French royal castle in the town of Vincennes, to the east of Paris, now a suburb of the metropolis.
Like other more famous châteaux it had its origins in a hunting lodge, set up for Louis VII about 1150 in the forest of Vincennes.  In the 13th century, Philip Augustus and Louis IX erected a more substantial manor.
To strengthen the site the castle was greatly enlarged replacing the earlier site in the later 14th century. A donjon tower, 52 meters high, the tallest medieval fortified structure of Europe, was added by Philip VI of France, a work that was started about 1337. The grand rectangular circuit of walls, was completed by the Valois about two generations later (ca. 1410). The donjon served as a residence for the royal family, and its buildings are known to have once held the library and personal study of Charles V. Henry V of England died in the donjon of dysentery in 1422 following the siege of Meaux.
In the Château de Vincennes the relics of the Crown of Thorns were temporarily housed while the Sainte-Chapelle was being readied to receive them. A fragment that remained behind received its own chapel at Vincennes, probably built by Peter of Montereau (the probable designer of the Sainte-Chapelle in Paris).
Château de Vincennes also served as the military headquarters of the Chief of General Staff, General Maurice Gamelin during the unsuccessful defence of France against the invading German army in 1940. It is now the main base of France's Defence Historical Service, which maintains a museum in the donjon.
More info on Wikipedia.
Official site of the castle: http://en.chateau-vincennes.fr