I remember hearing about it as a kid: People who found an abandoned line of the Metro and started a new civilization there. The way I heard it, there are at least hundreds of people in the society. They eat, sleep, have babies, etc. But they never see sunlight.
I suppose that at least a few need to have contact with the outside world for food and water.
Anyway, now that I’m older, it sounds more like an urban legend. Any factual evidence one way or the other?
Oops. This should be in General Questions. Sorry.
Perhaps you are refering to the Paris Catacombs. They are the largest tunnel system under a city in the world. 560 miles worth. Nobody lives there though.
While I can’t answer the specific question about Paris, there is a similar group in New York. The documentary Dark Days (2000) by Marc Singer follows those who live in that group.
Oh, additionally there was a book about the New York homeless people that moved underground in the abandoned rail system. It was, I believe, called The Mole People. Never read it, but heard some friends mentioning it.
Seems likey Paris has some homeless people, and seems likely they have abandoned areas of the subway system. I wouldn’t call a bunch of homeless people a society though. 
I read the Mole People. It was written by a female journalist who wanted to find out about them. She continually got deeper and deeper into the tunnels both physically and metaphorically. One time her guide believed that she saw him commit a murder and then it got even more horror filled. By that time she finally realized that the tunnels were no longer safe for her. The book is very good and reads as several short stories (like you would read in a newspaper) that are sometimes intertwined, sometimes not. All of them were very captivating. One of the people she wrote about, I thought I saw on one of the daytime talk shows in the early 90’s. He was going to college for some degree or other but lived in the tunnels to save money.
The TV show was called “Beauty and the Beast”, starring Linda Hamilton and Ron Perlman.
[Moderator Hat ON]
Moving to General Questions.
[Moderator Hat OFF]
Don’t know about the Metro, but there sure is a guy who lives in the airport over there.
http://www.snopes.com/travel/airline/airport.htm
Slight hijack, but couldn’t resist.
Actually, Rubicon, if you’re going to hijack, you ought to do it with Cecil’s column, Has a guy been stuck in the Paris airport since 1988 for lack of the right papers?
This interesting site, by an enthusiast who explores the NYC subway, is skeptical of the more striking claims made in The Mole People.
There is also certainly plenty of lore, of varying degrees of plausibility, associated with the Paris Catacombs and it wouldn’t surprise me if such a claim had been made about them, but I’ve never come across it before.
I think I’ve found matt_mcl Parisien(ne) counterpart (except he or she hasn’t had time to update since 2001 
):
http://membres.lycos.fr/metro/
The “inattendu” section seems to be where something like this might be. I’ve had no luck finding anything with the site’s search engine, but I don’t know any appropriate French search terms, either.
It seems entirely likely that there a considerable number of homeless people living more-or-less permanently under the streets of Paris.
Big cities have homeless people, including long-term homeless people. Under the streets is one place for them to find space.
About twenty years back I worked for a homeless shelter in St. Louis. The ground in downtown St. Louis has been built-up from its natural level; beneath the streets there are places where there are artificial caverns several stories high, filling in spaces between building foundations, sewer lines, etc. It was a common practice for staff from the shelter to go down into some of the caverns to look for people who were camping out.
In New York City there are a fair number of these people who are, in fact, regularly employed, but unable to afford anyplace else to live.
I recall a report on an NPR news show some years ago in which there was a discussion of people who live in packing crates and similar accomodations in access tunnels leading off from the subway system. I recall in particular an interview with a policeman who told of approaching such people in the belief that they were vagrants, only to have them go into their “houses” and produce their maid uniform, security guard uniform, etc.
As noted earlier in these posts, such people in New York have been the subject of at least one documentary film.
But an actual society of underground dwellers, a culture of people who live and die without seeing the sun? I smell an urban legend, and not a very original one.
John Cheever wrote a short story about a man who decides to try living in a department store, hiding during store hours and coming out after closing. He learns there is a whole colony of such people in the store already, including a young woman who grew up there after becoming lost in the store as a small child. He also heard about people who live in mortuaries; IIRC, there was some hint that they were cannibals. The story was silly, but memorable. I recall that either Time or Newsweek suggested that the story (the title escapes me just now) was one inspiration for the TV series Beauty and the Beast, which concerned a colony of people living in tunnels under the New York subway system. A similar idea figured in the first episode of the deservedly short-lived series Freaky Links.
These stories bring to mind the related urban legend that there are alligators (sometimes said to be giant and albino) living in the New York sewers.
I have read that there is a legend in London that a “race” of cannibals living under London. It is interesting to speculate whether these stories were an influence on H.P. Lovecraft, or whether Lovecraft, who dealt with similar ideas in stories such as Pickman’s Model and The Rats in the Walls, was a source for the legend. Another story I have heard is that herds of ferocious man-eating hogs live under London.
Of related interest are stories about individuals who live for years in hiding in an attic, the space between two walls, etc. There are documented cases of this, though extremely rare. Ralph Ellison’s book Invisible Man deals with such a person who makes a suite of rooms in a cellar space. Arthur Machen told a story at second or third-hand about a real estate agency in London which got a rent check every month for years for an address which did not exist. Finally a building the company managed was torn down, and it was found that there was an unnoticed crawlspace filled with furniture.
Another thought: recently (that is, within the last couple of months), National Public Radio aired a report about the increasing numbers of homeless people who have taken up residence in
Russian subway systems. I believe the report focused on either St. Petersburg or Moscow.
Everything in that book is bullshit. Even being only casually familiar with the history and design of the NYC tunnels you can spot several obvious lies and gross exaggerations. The linked site does a good job of debunking some of the more obvious ones.