The Origin of the World depicts a close-up of the female anatomy and now hangs in the Musée d'Orsay. Part of Courbet's private collection, it was considered far too risqué to exhibit at the time and could have seen the artist sent to prison on charges of "affronting public and religious morals." Its power to shock endures, as in 2011 Facebook blocked a Danish artist's page for publishing an image of the nude oil painting. The explicit work was part of a much larger tableax depicting a full female body based on Irish model Joanna Hiffernan, also Courbet's lover. It is thought Courbet severed the head from the body to avoid any scandal for his model. Courbet sold the most daring part of the tableau to Khalil Bey, a Turkish-Egyptian diplomat and avid collector of erotic art, who would show it to guests from behind a green curtain. After being pillaged during the Second World War, the work was bought by the celebrated psychoanalyst Jacques Lacan and finally ended up in the Musée d'Orsay in 1995. Thanks to the latest scientific techniques, experts at the art research centre CARAA were able to align the two paintings via grooves made by the original wooden frame and lines in the canvas itself, whose grain matched. The length of the brushstrokes and the size of the brush hairs also tallied perfectly. Tantalisingly, other sections of the painting may still be at large, including one in which the model's hand holds a fluttering parakeet, a symbol of eroticism. Despite Mr Fernand's official stamp of approval, some Courbet experts were sceptical about the find. "I'm not convinced," said Frédérique Thomas-Martin, chief curator and head of the Courbet museum in Ornans, eastern France, the artist's birthplace. The work was "very far from other portraits of this woman (Joanna Hiffernan), even if I haven't seen it," she told Libération newspaper. There was no official confirmation of veracity from the national museum body, Les Musées de France, she added. Mr Fernand dismissed such reservations. "She has the right to think what she likes," he told The Daily Telegraph yesterday. As for the Musées de France, I don't give a damn what they think. I am the official Courbet specialist and I have said it is by him. These Civil servants haven't even seen the work. He said he was not sure the discovery was positive from an artistic point of view, however. " (The Origin of the World) loses that kind of marvellous mystery and symbolism from the moment you stick a head on it - that's why Courbet took it off," he said.