A Swiss museum is to announce Monday whether it will accept a German recluse's bequest of a spectacular trove of more than 1,000 artworks hoarded during the Nazi era.
The decision, to be revealed at a press conference in Berlin, could determine the fate of priceless paintings and sketches by Picasso, Monet, Chagall and other masters that were discovered by chance in 2012 in the Munich flat of Cornelius Gurlitt.
Gurlitt, who died last May aged 81, was the son of an art dealer tasked by Adolf Hitler to help plunder great works from museums and Jewish collectors, many of whom perished in the gas chambers.
While media reports and sources close to the case widely expect the Museum of Fine Arts in Bern to accept the inheritance, all note it comes with a heavy price attached.
However an outstanding legal challenge may still muddy the waters.
"If I were a betting man, I would say that the Kunstmuseum Bern will be accepting the collection," London lawyer Christopher A. Marinello told AFP. "That is what I'm counting on."
Marinello represents descendants of prominent Paris art collector Paul Rosenberg on a claim to a long-lost Matisse painting found among 1,280 works in Gurlitt's Munich flat.
More than 300 other works were discovered in a home Gurlitt owned in Salzburg.
Although he was never charged with a crime, the German authorities confiscated all of the Munich pieces and stored them in a secret location.
Gurlitt struck an accord with the German government shortly before his death to help track down the paintings' rightful owners.
But his anger over his treatment reportedly led him to stipulate in his will that the collection should go not to a German museum but to the Swiss institution, which would now have to sort through the claims.
News weekly Der Spiegel reported that the deal to be announced Monday would see the Bern museum accept the inheritance but would leave nearly 500 works in Germany suspected of being looted until their rightful owners can be identified.
The Salzburg works would go to the Bern museum, which would assume responsibility for determining their provenance, according to Spiegel, which did not cite its sources.
- 'Avalanche of lawsuits' -
Should the Swiss museum unexpectedly turn down the offer, the pieces would be divided up among relatives of Gurlitt, who never married and had no children.
Ronald Lauder, the head of the World Jewish Congress, declined to comment ahead of the press conference.
But he told Spiegel this month that the Swiss museum should not accept the inheritance, saying it "would open a Pandora's Box and cause an avalanche of lawsuits".
Underlining the point, one of Gurlitt's cousins, 86-year-old Uta Werner, said Friday she was contesting Gurlitt's fitness of mind when he wrote the will naming the Bern museum as his sole heir.
This could return the case to legal limbo, with ageing Jewish descendants left to fight for their claims in German courts for years to come.
After the discovery of the Gurlitt trove came to light in a magazine article last year, Jewish groups and the US and Israeli governments put pressure on Germany to establish a task force to investigate the works' provenance.
In the case of the Matisse painting, called "Seated Woman" and believed to be worth around $20 million, the panel determined in June that the work was "Nazi loot" stolen from Rosenberg.
His heirs include French journalist Anne Sinclair, former wife of ex-IMF chief Dominique Strauss-Kahn.
Marinello noted that the museum -- unlike individuals -- would be bound by the Washington Principles, a 1998 international agreement on returning art stolen by the Nazis, as well as the 1986 International Council of Museums code of ethics.
"My clients have been extremely patient with German authorities throughout the process and enough is enough," he said.
Meanwhile the acquisition of the Gurlitt hoard would dramatically increase the prestige of the Bern institution, Switzerland's oldest art museum.
Stephan Klingen of Munich's Institute for Art History said the public interest in the collection was "enormous".
"I think this is a chance to show people right before their very eyes how problematic the handling of art and art works after the war was," he told German news agency DPA.