A businessman has been told a painting he paid £100,000 for will be destroyed after it was ruled a fake.
Martin Lang bought what he thought was an original work by Russian-born artist Marc Chagall in 1992.
Its authenticity was tested by experts for BBC One's Fake Or Fortune? and it was sent to the Chagall Committee in Paris which said that under French law, it should be destroyed.
But the decision has been criticised as "extreme, inappropriate and thuggish".
Philip Mould, the programme's art expert said decisions were never final and could be revisited with modern science and technology.
"So it seems to me bombastic in the extreme to assume that their decision is absolutely right forever," he said.
Chagall, who died in France almost 30 years ago, was born in Belarus in 1887.
Regarded as a pioneer of modernism, his work can sell for millions of pounds.
The Chagall Committee is run by the artist's grandchildren to protect his reputation in the art world.
Mr Lang, 63, a property developer from Leeds, has asked the committee to mark the watercolour - a nude said to date from 1909-10 - as a forgery and then return it or give him a guarantee he will be reimbursed if it is later ruled as genuine.
He is still waiting for a reply.
"I had no idea that anyone would take such a draconian view," he said.
"They say they want to counter forgery but I think this will have the opposite effect of deterring honest people like myself from coming forward."
Fake Or Fortune? host Fiona Bruce said: "A decision like this forces the owner of any painting to play a kind of Russian roulette with their precious artwork.
"The only way for Martin to authenticate his painting was with the Chagall Committee, he had no other choice.
"But it was never made clear to him that if they didn't like the look of his painting that they would burn it.
"How can anyone ever approach this committee with a painting again if this is how they react?"
Fake or Fortune? is broadcast on Sunday, 2 February, at 18:00 GMT on BBC One. It is available nationwide for seven days thereafter on the iPlayer.