Last strolls among the dead before work begins at the Catacombs of Paris

"It's bad for preserving bone mass... and for my hair," Isabelle Knafou jokes, her eyes turning towards large basins discreetly placed on a wall of human bones.

The incredible typology of the place, with galleries dug 20 meters underground, sometimes requires "making do" to preserve this "fragile" place, summarizes the administrator of the most famous Parisian museum-cemetery.

A pipe runs between the skulls and femurs to empty the water into a bucket, soon followed by gutters. An "old-fashioned system," inspired by medieval techniques used in fortified castles, where drains integrated into the walls allowed rainwater to be evacuated.

In this network of galleries dug from the 12th century onwards to extract limestone for the building which became a municipal ossuary, the remains of several million people who died in the capital between the 10th and 18th centuries, from various Parisian cemeteries, were stored.

In these galleries, the humidity promotes the growth of microorganisms that gradually settle on the bones. The atmosphere of the Catacombs also changes under the influence of bacteria and CO2 released by its 600.000 annual visitors.

Starting Monday, the museum will close its underground area to the public for approximately six months for major conservation work. The "meditative and spiritual" walk among the dead will resume in spring 2026.

"If we don't want to become a Lascaux cave (closed to the public, editor's note), we have to take drastic measures," explains Ms. Knafou.

Beyond the overhaul of the technical installations—electricity, ventilation system, etc.—a "renewed scenography" will be offered to visitors, says Hélène Furminieux, head of communications and public relations. Without betraying the "authentic" and even "somewhat raw" spirit of the place, adds Isabelle Knafou.

The materials needed for the work will be transported through the same shafts that were used to bring up stones in the Middle Ages and to lower bones in the 18th and 19th centuries.

In total, the cost of the works is estimated at 5,5 million euros.

The graffiti scrawled everywhere will be removed. "Many people wrote on the walls in the 19th century," explains the administrator, walking along the electrical conduits covered in scribbles in a narrow corridor. "It's almost part of the culture, even if we fight against it."

A register, the ancestor of the guestbook, had nevertheless been put in place from the very first day of the opening of the Catacombs in 1809, "so that people could write in it rather than on the walls," adds Hélène Furminieux.

Avoid thefts

For nearly 800 meters, visitors walk just centimeters away from the bones, with no barrier separating them from their distant ancestors, human remains dating from the Middle Ages to the French Revolution.

The hagues, the name given to the more than 200 walls of human bones on the site, are formed of femurs and tibias stacked one on top of the other. The skulls, however, serve only a decorative purpose, being too fragile to support the structure.

Only a few signs indicate that touching them is forbidden. But the temptation to grab an ulna or write on a skull is sometimes too strong for a handful of visitors. "To prevent theft," the bones are cemented in place, "because the great national sport was leaving with a souvenir," explains Ms. Knafou.

"Some visitors, especially Americans, come a little to scare themselves, without realizing that these are real bones," she says. "These are our ancestors, and we explain that nobody would want anyone touching or playing with their grandmother's skull."

Without understanding the philosophical quotes engraved in French along the route, Ricardo and Cintia Morales perfectly grasped the solemnity of the place. "We organize a mass or a celebration (for the Day of the Dead, editor's note)" for our ancestors, explains the Mexican-American couple for whom "preserving" their memory is a long-standing tradition.