In an extraordinary discovery, a retired French doctor was holding onto an original Leonardo da Vinci drawing in a pile of random low-value sketches.

It is the first new da Vinci to be found in 15 years according to the French auction house Tajan.

“This is an exciting new discovery,” said the Metropolitan Museum of Modern Art.

The drawing is a pen and ink study of Saint Sebastian with two scientific studies on the reverse side.

Carmen C Bambach of the Metropolitan Museum of Art in New York believes the sketch was created between 1482 and 1485, when da Vinci was working in Milan.

Tajan values the work at 15 million euros or more than $20 million Canadian.

While pleased with the news the doctor reportedly told Patre that he has “other interests in life other than money.”

According to The New York Times, the sketch came to Tajan’s attention when 14 unframed drawings were taken to the auction house, to be valued by the director of Old Master pictures, Thaddee Prate.

After spotting the drawing, Prate got a second opinion from Patrick de Bayser, an independent dealer and adviser in Old Master drawings.

Bayser recognised the work was done by a left-handed artist, da Vinci was famously left-handed.

Prate then reached out to a third expert for further affirmation.

The drawing was authenticated by Bambach, who is a world-renowned expert on Leonardo drawings.

“The attribution is quite incontestable,” Bambach told the New York Times. “What we have here is an open-and-shut case.”