The painting, Water Lilies, is at the centre of a dispute between French authorities and the descendants of a Jewish art dealer, Paul Rosenberg, whose house near Bordeaux was looted in 1940.

The painting was discovered after the war in a warehouse in Hamburg, where it was tagged as being part of a collection owned by Hitler's Foreign Minister Joachim von Ribbenthrop.

It has been part of the collection of the Museum of Fine Arts at Caen, western France, since 1974, and is currently on show at the Boston Museum of Fine Arts in the US.

Origins being investigated

Now an investigation is under way in France to check the painting is part of Rosenberg's collection.

"If the research currently under way confirms that Water Lilies is indeed the painting by Claude Monet which featured in the Paul Rosenberg collection and that this work still belonged to this collection when it was stolen, the painting obviously will be returned to its rightful owner," a museum spokesperson said.

London's Royal Academy was hoping to include it in an exhibition of Monet's work from 23 January - but France will not allow it to show the painting until the investigation is complete. Authorities fear Rosenberg's family could take legal action to seek the return of the painting.

But it can still be displayed in Boston because US law is different, according to the Royal Academy's David Gordon.

"The US has a law which says if you want to pursue the claim on a looted work of art, you have to pursue it in the country in which it usually resides, in this case France," he said.