Degas' Les Choristes was one of 20 of his works in the Marseilles show
An artwork by Impressionist artist Edgar Degas has been stolen from a Marseilles museum, police have said.
Les Choristes (The Chorus) was missing when staff at the Catini Museum opened the premises on Thursday morning.
There were no signs of a break-in, said Jacques Dallest, the French city's public prosecutor.
Local police originally said that its value was £26m, but France's national museum service subsequently put its worth at £710,000.
The item was on loan from the Musee D'Orsay, in Paris, as part of an exhibition of Degas' work which was due to come an end on 3 January and travel to Italy and Canada.
The museum will now remain closed while the theft is being investigated, including the examination of CCTV footage from security cameras.
Mr Dallest also told Agence France Presse that police are looking into the possibility that the artwork was stolen by an intruder, a visitor or a museum insider.
Les Choristes, which dates from around 1876, is a colourful pastel work which depicts a male line of singers in the midst of performance.
Earlier this year, Degas' bronze sculpture of a young female dancer sold at auction in London for £13.3m.