VIENNA - A Jewish family's claim to one of Austria's most famous artworks by Gustav Klimt is shaping up as a test of the country's restitution drive and willingness to right old wrongs.
The 34-metre-long (112-foot) and two-metre-high "Beethoven Frieze", a jewel of Jugendstil art, has been a Vienna tourism highlight since 1986.
But the heirs of former Jewish art collector Erich Lederer - who fled to Switzerland during World War II - say the Austrian state obtained the masterpiece through dubious means and are claiming it back.
"Our clients want a wrong to be redressed," lawyer Marc Weber told a press conference Thursday, two days after the Lederer family filed a claim for restitution with the Austrian culture ministry.
"It is also immensely important for Austria's international image how it deals with its own history in cases such as this," he added.
The case is the biggest since Austria in 2006 had to give up Klimt's prized "Portrait of Adele Bloch-Bauer" to heirs of the previous owner.
The latest restitution demand is also the most high-profile one to emerge under a 2009 restitution law, which covers not just Nazi-looted art but also art that was bought by the Austrian state after the war under sometimes dodgy circumstances.
"The 'Beethoven Frieze' is a textbook case for this new restitution law," according to legal expert Georg Graf, who wrote one of the reports laying out the case for restitution.
Seized by the Nazis, along with the rest of the Lederer family's important art collection, the fresco - which depicts man's path to happiness - was returned to Erich Lederer after the war.
But through "artful tricks" and an export ban, Austria compelled him to sell the work to the state in 1973 for less than half its worth, according to Graf.
Thanks to the 2009 law, the heirs now have a case, lawyers and experts agreed.
"By returning the 'Beethoven Frieze', Austria can set an example and take a leading international role in terms of restituting looted art," Weber said.