The Hall of Apollo is incredible. Every inch of it (although it's in Paris, so I suppose "every centimeter of it" would be more appropriate) is a work of art.The walls, the doors, the ceiling & floor are all covered in a giant calendar which depicts all of the season, the zodiac and the arts & sciences.This is also where the crown jewels are kept...
...so, if you simply must rob the place (which I advise STRONGLY against), this may be a good place to start.