German daily Bild reported the unidentified heirs are claiming ownership of Henri-Edmond Cross's "Regatta in Venice" from 1903/04, which is currently on show at the Barberini Museum in Potsdam, near Berlin. The painting is on loan from the Museum of Fine Arts in Houston.
The painting originally belonged to Jewish-French collector Gaston Levy, but was confiscated by the Nazis in 1940, said Christoph Partsch, a lawyer for the family. "My clients found out only now about the existence of this long-missing painting and they demand its return," Partsch told The Associated Press.
The lawyer said the family lives in Europe, but didn't want to further identify them. The Potsdam state court has given the Barberini Museum until next week to respond to their demand, Partsch said. The court on Wednesday afternoon confirmed that it had received a request for the return of the painting by two people whom it didn't further identify.
The Barberini Museum said it was in touch with the Houston museum and that both museums "see the clarification of the legitimate owner as an urgent obligation." After the war, the painting surfaced in the United States where in 1958 it was donated to the Houston museum, the Barberini museum said.
"The question of provenance is especially important because Cross is an artist whose work has been forgotten in Germany due to confiscations by the Nazis from German collections as well," the museum said in a statement.
The impressionist work is painted with oil on canvas in the pointillism style and shows several gondolas on the water and the city line of Venice in the background. In a statement, a spokeswoman for the Museum of Fine Arts in Houston said a review has begun of the allegations. However, spokeswoman Mary Haus said "aspects of research to date contradict a number of the plaintiffs' assertions."
Associated Press writer Terry Wallace in Dallas contributed to this report.