Beneath the city of light, there lies, unknown to many Parisians a parallel city of darkness, a city of shadows. A tiny part of this subterranean city - the official catacombs - is open to the public. The greater part, a 300km network of 18th-century passages and medieval quarries, 80ft underground - below the sewers, below the Metro, below the car parks and the air-raid shelters - is supposedly sealed off and banned to all but a handful of authorised people. Supposedly.
For more than a century - intensively in last 30 years - the tunnels, the "secret catacombs", have become an adventure playground more extensive than the Paris Metro, a labyrinth of innocent fun and discovery for a legion of urban pot-holers and thrill-seekers known as cataphiles.
Armed with a lantern and overalls, they climb down into the depths to explore, to paint, to create elaborate carvings on the walls, to hold parties and concerts and play cat-and-mouse (or cat- and-mole) with the special catacomb police patrols. Entering this labyrinth has been illegal since the 1950s.
In recent days, this hidden, mostly innocent world has been (to the chagrin of many cataphiles) dragged into the open. The Paris police announced that they had discovered, deep under Trocadero, across the river from the Eiffel Tower, a subterranean cinema in a cavern 60ft long by 60ft wide, with seats, a screen, a bar, bottles of whisky and illegal cable connections to the city's mains electricity supply.
A few days earlier, there was a brief flurry of alarm when the prison service announced that it had discovered "tunnels" underneath the high- security Sante prison in south-eastern Paris. Was this an attempt to stage a Great Escape? Was it a terrorist plot to blow up the creme of the French criminal classes? It rapidly emerged that the "tunnels" were only a few feet long and were not really underneath the Sante. They had merely been dug "in the direction" of the prison from one of the passages in the vast maze of catacombs under the city's Left Bank. Mainstream cataphiles believe that the digging may have been an attempt by an "extreme" group of anarcho- cataphiles to achieve one of the holy grails of cataphilia - to break in to the Sante prison from below (just for the hell of it).
The "cinema" under Trocadero is also something of a mystery. Police spoke darkly, at first, of a possible connection with ultra- right-wing groups or satanic rites. Then, more prosaically, the authorities began a formal criminal investigation for the "theft of electricity".
Both police and cataphiles are now coming around to the conclusion that the "cinema" was a spoof, set up by a group of underground jokers - maybe the same group as the Sante prison jokers - to annoy the police and tug the strings of the media. A bad idea, the mainstream cataphiles say. A very bad idea. Every time something of that kind happens, it provides an excuse for the authorities to clamp down on cataphile activities and, worse, "inject" concrete, rubble and power-station ash into some of the tunnels to close them down forever.
Since the revelations of recent days, police have redoubled their activities underground and dozens of cataphiles have been briefly arrested. Some, to their amusement, have found themselves being interviewed by the anti- terrorist police.
So what are the catacombs, and who are the cataphiles? The network of passageways and artificial caverns began as quarries to provide the limestone for Notre Dame cathedral, the Louvre and other buildings in Paris, from the 12th century onwards. In the late 18th century, when streets started to collapse into the forgotten voids below, an elaborate system of inspection tunnels and bulwarks was constructed deep under the city.
Since the freelance exploration of these catacombs began in the early 19th century, there have always been dark rumours of satanic or criminal or extreme sexual activity underground. …