*beep*
I live in the suburb of paris, I go in the catacombs every month with friends to have fun and there is nothing strange in there.
OK there are some skulls (not a lot), there used to be a cinema, lot of people are going in (around 40 people everyday and more than 100 in the WE).
No rats, no ghosts, no crocodiles.
here are some links of website of my friends.
http://ktaxplorer.blogspirit.com/
catacombes.web.free.fr
http://www.catacombes.explographies.com/ (very good link with an english version, maps etc...)