PARIS — A little over eight years ago, French investigators were stumped after a small painting by the Impressionist master Edgar Degas was stolen from a museum in the Mediterranean port city of Marseille.

The painting, a colorful pastel from 1877 depicting singers on a theater stage, appeared to have been unscrewed from a wall, but there was no sign of a break-in. The police briefly detained a night watchman, but then released him.

Years went by. The painting, titled “The Chorus Singers” and thought to be worth nearly $1 million, was nowhere to be found.

Until now.

In a surprising twist, the French authorities confirmed on Friday that the painting had been recovered on Feb. 16 by customs officers randomly searching the luggage compartment of a bus at a highway stop in Ferrières-en-Brie, about 18 miles east of Paris.