I have been guided by cataphiles in the past, although not in Paris. I went to some of the underground quarries in Bougival and it is in retrospect that I realize how incredibly dangerous it all was. In one trip, we were sloshing through something like a mine tunnel held up only by rotten beams, and in another we broke through into quarry levels where there was no oxygen left and until we crawled out through another small hole in the roof, we were wondering if we were going to pass out (and this was a group of 20 people!).

The unauthorized Paris catacomb areas are child's play compared to this, and the only risk that you might incur if you go to these areas is the increasingly high fines that the subterranean police apply when they catch you. But most people who are so inclined would not miss it for the world.

I can't remember if it was BBC, Sky or CNN International, but I saw a segment a few weeks ago on the cataphiles in Paris, as well as the police force. I don't have any actual advice to offer, but just wanted to say that I am jealous of your plans.

I explored the Catacombs (without a guide) but only in the 'authorized sections' - while I am sure there is some excitement and uniqueness to the 'unauthorized areas' I can assure you there is plenty of macabre and unusual stuff to photograph in the allowed sections.

WOW! @ Kerouac how did you find our cataphile? Now that you have shared your story, going with a group of people may be a better idea than trying to go it alone. Running out of oxygen is something that I never considered. If I did explore alone, I doubt I would have enough confidence to go very deep.
Did you do a one day trip or did you stay overnight? Any suggestions on what I should take with me? I realize I will need some type of rain boot to get through murky areas and a head light. In some pictures looking online it looks as though there are some areas of the catacombs that are lit by electricity or candles? Do have any insight on this?
Although dangerous your story was pretty amazing. There aren’t many people that can say they have had an experience like that…well maybe 19 others. Thanks for sharing I enjoyed it.

@MLtimes I know exactly what CNN peice you are referring to.I came across it online when researching. I decided that if I was going to go this trip alone, I was going to do everything my friends would never do with me. Lol
@albionbythesea thanks for the insight. I didn't know you explore the authorized sections without a guide. Where did you enter and end?

Forgive the horrible spelling I'm at brunch and responding on my phone!

We would go underground around midnight and come out around 6am. Everybody brought food and drink with them.

The official catacombs now are lit by electricity, but if ever you go on a trip to closed areas, you must have your own lighting. My contact in the old days was a bearded guy called "Papy" but the very reason that he took groups to Bougival was because the Paris catacombs had been sealed off too well and were patrolled too well.

One of the best places that you could possibly go is the "carrière des lions" in Bougival. The name is because there is an apartment complex right in front with stone lions on the gate posts. It used to be very easy to get in through the old quarry gate, but I'm sure that has changed. This place is so huge that there are rusted hulks of cars in the first main tunnel.

I actually led two friends there a number of years ago. Even though we didn't try anything really dangerous, nobody had any idea where we were and if anything had happened, we might have only been found a week later by another group of cataphiles. If you saw The Lord of the Rings and remember the scenes regarding the Mines of Moria, that is exactly how big and how creepy it is.

There was an article on BBC on this recently. I'm not sure if the UK firewall restricts this to our Islands but the link is http://www.bbc.co.uk/programmes/b01b9h73

also this BBC link from 2011 http://www.bbc.co.uk/news/world-europe-14553836