The Louvre Museum, in Paris, is appealing to the public to help raise 1m euro (£853,000) to keep a 16th Century oil painting in France.
Owners of The Three Graces, by German Lucas Cranach the Elder, have agreed to sell for 4m euros (£3.4m) to the Louvre which has so far raised 3m (£2.6m).
The museum said it was "an exceptional piece which needs to be part of the national collection".
The Louvre has until 31 January to raise cash before it goes on open sale.
A spokeswoman said the museum would do "everything we can to get hold of it".
The work, painted in 1531, is an ironic take on the Renaissance three graces theme.
It depicts the three nudes in a daring pose, all wearing solid necklaces, with the central figure wearing a feathered red hat.
Louvre curator Vincent Pomarede said the work could become one of the museum's most popular pieces.
"It's a work that's amusing, disconcerting, mysterious and very sensual," he said.
Those who make donations will be named on the Louvre's website and in documents.