The hands on the old clock in the Panthéon are stuck at 10:49, seemingly as dead as the French heroes and luminaries who are buried far below in the building's 250-year-old crypt.
Tucked into a back corner, above a memorial plaque to the dead of the First World War, the 19th century clock has not marked the passage of time for more than 40 years.
But it's not for lack of trying.
In 2005, the venerable monument in the old Latin Quarter was invaded by a clandestine group of self-appointed restorers. They set up shop on a drafty catwalk by the rusted cast-iron gears and pulleys of the long-forgotten clock. Working at night, long after the Panthéon doors had clanged shut, they secretly cleaned machinery and refurbished parts.
After a year of nocturnal fiddling, they announced to the surprised administrator of the building that the clock was ready to run again. He was not amused. He alerted the Centre for National Monuments and late last year, four of the underground repair crew, two men and two women, were hauled before a Paris judge on charges of damaging state property. The case was dismissed, but the government seems in no mood to forgive and forget. No one has restarted the clock. The Minister of Culture is preparing a law to make it a crime to be in a historic monument after hours.
The Panthéon clock caper is just the latest entry in the wacky folklore of underground Paris, a sort of parallel world inhabited by people who delight in going where they are not supposed to go in the 1,500-year-old capital. Some of these adventurers are just out for fun; others have a political agenda, while some see the city's hidden corners as a vast urban canvas.
For years, amateur adventurers have been descending with miners' lamps to the city's subterranean labyrinth of tunnels, well shafts, ancient quarries, Gallo-Roman baths and long-forgotten crypts hidden beneath churches.
Some of the underground byways are full-fledged tourist attractions, like the Paris sewers and catacombs. Authorized concerts are sometimes staged in subterranean caverns that date back centuries. A few of the old quarries, rediscovered and scrubbed up by history buffs, are even classified as national treasures.
But hundreds of kilometres of below-ground passageways are supposedly restricted or off-limits. So are countless medieval storerooms, abandoned cellars and forgotten chambers inside national monuments and government buildings. This forbidden Paris has long exerted a magnetic attraction for curious teenagers and other iconoclasts.
Some seem simply to enjoy the challenge of dropping through a manhole and occupying one of the caves to drink, picnic and paint graffiti on tunnel walls. Calling themselves urban explorers or catacomb crawlers, they post down-under pictures of themselves on dozens of Internet sites with names like Ktaliste and Cataphiles.
"The regulars are like a family," said Luc Bard, a 21-year-old communications student who started exploring the caverns below street level in his northwest Paris neighbourhood five years ago. "Sometimes we just sit around and talk. Sometimes someone will talk about the history of the city. We don't harm anything. It's just a place, our place, to get away."
For others, underground Paris is a stage for an alternative art scene. Some of the more popular caverns are named for the frescos painted on the walls - the Ghost room, for example, or the Catapult room. In 2004, a group calling itself "the perforated Mexican" set up a small movie theatre in a grotto nine metres under the Trocadero esplanade opposite the Eiffel Tower. When the police raided the place, they found the purloined electrical line cut and a handwritten note that said, "Don't look for us."
Still other underground denizens, like the freelance clock restorers who penetrated the Panthéon, claim they seek out forbidden zones to rediscover the national patrimony and save it from official neglect.
"If you ask the administration to restore these places, they talk about budget problems and all the little reasons they can't do anything," said Lazar Kuntsmann, a video filmmaker who is the spokesman for the covert clock team. "Anyway, we couldn't stand to do what we do in an institutionalized way."
His team called itself Untergunther, a nonsense word that members made up to describe the German rock music they sometimes listened to while the clock repairs were under way. They were all old friends who had been living or hanging around the cramped bars and twisty streets of the Latin Quarter for most of their lives.
The core group began slipping into grottos, subway tunnels and even the Panthéon itself in the early 1980s. Scrabbling about underground was then all the rage among students, and when the Paris police mobilized to stop them, the activity became a rite of passage.
Mr. Kuntsmann and his friends, it appears, were hooked for life.
Early on, he said, they invented a name for themselves, Ux, and still regularly initiate fresh enthusiasts into what they like to see as a secret society. Every year, Ux runs what it calls a "school" for new members in how to bypass locked doors, tap into phone and electrical lines and, of course, traverse underground Paris. The group that organized the covert grotto cinema four years ago, he said, was an Ux affiliate.
Ux has no political agenda, according to Mr. Kuntsmann. Its philosophy, if there is one, is spontaneity. The core members, who describe their mission as "cultural restoration," have conventional day jobs. One of those charged in the Panthéon case is a nurse. Another, tellingly, is a trained clockmaker.
"There's an inexhaustible list of projects to take care of," said Mr. Kuntsmann, who refused to say what, if any, other projects his friends have completed. "It's a question of feasibility for us. We look at whether we have the right expertise, whether the project would be durable and whether there are people capable of devoting a year of their lives to the restoration."
The Panthéon clock fit the bill. But the experience was not quite as enjoyable as it was when they were younger. "It was dirty, dusty and abandoned and it was freezing cold," Mr. Kuntsmann said. "And, you know, we are now all of a certain age."
Nonetheless, the episode had a delicious kind of logic for Mr. Kuntsmann,. "You can't sue somebody for doing something good," he said. "And we repaired something."
He described it more romantically in a short video called Urban Exploration that he produced a few years ago.
"That passageway you travel each day, with your head down, is not completely hermetically sealed," says the film's narrator, as grainy scenes of locked doors and underground tunnels flash by. "Here and there are some openings that allow you to escape."