The photos you've seen online don't do this place justice - so make sure you come for yourself. I was lucky enough to arrive about 10 minutes before one of the guided tours (in English), which appear to take place on the hour (you may need to double check that, however, as some of the tours are obviously in French). I definitely recommend coming at a time that overlaps with the tour, though, as it was informative, fun, and often funny.