"The whole thing ran off a professionally installed electricity system and there were at least three phone lines down there." Three days later, when the police returned accompanied by experts from the French electricity board to see where the power was coming from, the phone and electricity lines had been cut and a note was lying in the middle of the floor: "Do not," it said, "try to find us."
There is an extensive network of catacombs under Paris, most of which is off-limits to the public, though frequented by groups of "cataphiles", who sound somewhere between the Cave Clan and the troglodistes in the film Delicatessen.
The recent discovery of three newly enlarged tunnels underneath the capital's high-security La Santé prison was put down to the activities of one such group, and another, iden tifying itself as the Perforating Mexicans, last night told French radio the subterranean cinema was its work.
Patrick Alk, a photographer who has published a book on the urban underground exploration movement and claims to be close to the group, told RTL radio the cavern's discovery was "a shame, but not the end of the world". There were "a dozen more where that one came from," he said. "You guys have no idea what's down there."