There is nothing quite like secret societies, especially when they do things like this. The Untergunther, the cultural restorative arm of the UX, an underground Parisian society, has restored a clock in the Panthéon in Paris unbeknownst to the museum. Check out this article in the Guardian about a Paris Underground. Pics of the the clock restoration can be found here. I wonder what other activities they have done throughout the city. For those who speak French here is the Untergunther site.