AVIGNON, France — Interested in opening a luxury hotel in the heart of Provence? Check out this real estate offering by the French government:

“Exceptional location at the foot of the Palace of the Popes, view of the Rhone River, 10,280 square meters. Ancient St. Anne Prison.” The property includes “detention cells, two gyms, a library, a cinema, infirmary rooms, a kitchen, and stores,” according to the advertisement on the French government’s Web site.

Avignon, the ancient walled Provençal city famous for a bridge immortalized in a nursery rhyme and a palace built for medieval popes fleeing the chaos of Rome, is searching for a buyer willing to transform its 1865 prison into a luxury hotel.

“It’s like a wart in the heart of the city,” said Michel Moreno, local head of France Domaine, the government agency charged with disposing of unused property. “We hope to turn it into something beautiful.”

The prison is one of dozens of properties across the country that the French government is trying to unload. Whether it’s a rural chateau or an urban high-rise, the goal is to boost state finances by selling off buildings that have become too costly or outdated to maintain.

An anonymous purchaser recently snagged the former residence of the commander of the French Foreign Legion, a 1960s house with a large swimming pool and garden just outside the southern city of Orange.

A Qatari developer snapped up an opulent Foreign Ministry building marketed as “ideally situated with immediate proximity to the Champs-Élysées and very near the Arc de Triomphe” for $600 million, with plans to turn it into a posh hotel.

The French government launched an aggressive property sales campaign in 2005. The sales have since jumped from $230 million a year to just over $1 billion last year.

St. Anne Prison, built during the reign of Napoleon III, was constructed atop the stone ruins of a 13th-century insane asylum. France shuttered the rat-infested prison in 2003, moving inmates to a new facility to comply with European Union regulations for more humane penal facilities.

Mr. Moreno is the main sales agent for the gloomy edifice. On a recent chilly day, he led visitors through the dark hallways, walking inside cells where thin brown blankets were rumpled on metal bunks and boxes of stale crackers sat on shelves, just as prisoners had left them.

“It will be very complicated to convert,” Mr. Moreno said. “But man has already walked on the moon. That was complicated and we managed.”

Mr. Moreno said architects estimate it will cost about $40 million to renovate the building. That job would require breaking through 18-inch cell walls, installing heating and air conditioning and generally transforming a sterile edifice into a 110-room hotel that would command top dollar from tourists and nearly double the number of four-star hotel rooms in the city.

Because renovation costs will be so high, city officials said the actual sale price of the buildings could be as low as $2 million.

As Mr. Moreno strolled the darkened hallways, skirting mounds of pigeon droppings, he described his vision for a hotel that would attract guests to a location that previous residents longed to escape.

The “best cells,” like no. 224, where artificial flowers sprout from a chipped vase on a dusty table, could become a presidential suite. But the artwork might have to go. Glancing at curling magazine pages taped to the walls, Mr. Moreno noted, “No Picasso or Matisse here, only Playboy and Penthouse.”

Two floors down, he stepped inside the closet-size solitary confinement cell.

Its use in a hotel conversion? Mr. Moreno said with a shrug, “Perhaps it could be used for rowdy children.”

The Justice Ministry has a lot riding on the sale of St. Anne Prison.