If Austria's Art Restitution Advisory Board decides Gustav Klimt's monumental Beethoven Frieze should be given back, it would mark one of the most spectacular art restitution cases for works looted by the Nazis.
The fresco, 34 metres (112-feet) long, two metres high and weighing several tons, is widely regarded as a central masterpiece of Viennese Jugendstil art nouveau from the early 20th century, drawing thousands of visitors every year.
The Nazis confiscated the 1902 work from the Jewish Lederer family in 1938.
After 1945 it was returned by Austria to the family heir Erich Lederer, living in Switzerland, who then sold it to the Austrian Republic in 1972.
His descendants say however that Lederer sold it under pressure because Austria refused to allow him to take the frieze out of the country, and that the reported sale price of $750,000 was too low.
If the advisory board recommends returning the work, which is now likely worth millions and is on public view at Vienna's Secession Building gallery, the final decision will fall to Austria's culture minister.
"Until now all ministers have always followed the recommendations of the advisory board, and this will be the case with the Beethoven Frieze too," ministry spokeswoman Kerstin Hosa told AFP.