PARIS, DEC. 6 -- Nine paintings that vanished in a brazen 1985 theft, including the Monet masterpiece that gave impressionism its name, were returned to Paris today after police found them in a Corsican villa.

Police said recovery resulted in part from information gathered from gangsters in Japan.

"It's the best Christmas present we could have," said Arnaud d'Hauterives, curator of the Marmottan Museum. He said Claude Monet's "Impression Sunrise" and the other works might be ready for re-display at the Marmottan by the end of the month after specialists treated them for damage caused by humidity.

D'Hauterives joined Culture Minister Jack Lang in praising the persistence of a special police art theft unit, headed by Commissioner Mireille Balestrazzi.

Balestrazzi, one of the highest-ranking women in the national police force, said the breakthrough in the case came during a 1987 trip to Japan to bring home four paintings by Camille Corot that had been stolen in 1984 from a museum in eastern France.

She said her team learned that a Japanese collector had been considering the purchase of one of the nine works. Additional information was obtained through contacts with the yakuza, or members of Japan's organized crime network. Some of the gangsters were approached by representatives of the thieves, she said, but refused to get involved.

Authorities said one man had been arrested in Corsica and about a dozen other people had been questioned, but they indicated that the thieves themselves remained at large.

The nine paintings from the Marmottan, along with an as-yet-unidentified 17th century painting, were found Tuesday in a villa in Porto-Vecchio in southern Corsica.

Balestrazzi said the theft was committed solely in hopes of profit.

The stolen paintings included five Monets, among them the priceless "Impression Sunrise," two by Pierre Auguste Renoir and one by Berthe Morisot, as well as a portrait of Monet. Their total value was estimated at the time at $12 million.