PARIS — A 400-year-old picture that might have been painted by Italian master Caravaggio has been found in an attic in southern France.

Eric Turquin, the French expert who retrieved the painting two years ago, says it is in an exceptional state of conservation and estimates its value at 120 million euros (about $135 million).

The picture, whose authenticity has not been established, had been left for more than 150 years in a property in the outskirts of Toulouse.

Called “Judith Beheading Holofernes,” it depicts the biblical heroine Judith beheading an Assyrian general. It is thought to have been painted in Rome circa 1604-05.

Turquin told a news conference on Tuesday that there “will never be a consensus” about the name of the artist.

Two Caravaggio experts he consulted with attributed the painting to Louis Finson, a Flemish painter and art dealer who was familiar with Caravaggio, Turquin said. Finson possessed a number of works from the Italian master and made copies of his pictures.

“But the third expert I met told me that it was not only a Caravaggio, but also a masterpiece,” Turquin said. “’Judith Beheading Holofernes’ must be considered the most important painting, by far, to have emerged in the last 20 years by one of the great masters.”

The picture has been awarded “National Treasure” status by French authorities, meaning that it can’t be exported for 30 months, leaving the national museums enough time for its acquisition.

While stating that the art work has yet to be authenticated, France’s ministry of culture justified its decision to ban the export of the painting because it “deserves to be kept on (French) territory as a very important landmark of Caravaggism.”

The owners of the house in Toulouse discovered the painting, which had been partially damaged by water, when they went to the attic to fix a leak.

They telephoned local auctioneer Marc Labarde. After using cotton wool and water to clean it, he recognized a 17th-century painting from the Caravaggio school.

“I told the owners they had found a beautiful picture and gave them an estimation that I do not dare say,” said Labarde, a close partner to Turquin. “Then I had it sent to Paris.”