The heirs of the Jewish banker and art collector Paul von Mendelssohn-Bartholdy are pressing ahead with their attempt to reclaim Vincent van Gogh’s Sunflowers, arguing that the masterpiece was sold under Nazi duress in the 1930s.

The family, represented by Julius H. Schoeps, Britt-Marie Enhoerning and Florence von Kesselstatt on behalf of more than 30 beneficiaries, is challenging the Japanese insurance giant Sompo Holdings. The case was first brought in 2022 but dismissed by a lower court in June. The heirs have since appealed to the US Court of Appeals for the Seventh Circuit, where a panel of three judges heard arguments earlier this month.

At the heart of the dispute is Van Gogh’s luminous still life, painted in 1888–89 and now valued at around $250m. Sompo, then known as Yasuda, bought the painting at Christie’s in London in 1987 for a record $25m and now displays it at the Sompo Museum of Art in Tokyo. The heirs argue that the company failed to acknowledge provenance records identifying Mendelssohn-Bartholdy, who was forced to liquidate much of his collection under the Nazi regime, as a previous owner.

The lawsuit is being pursued under the Holocaust Expropriated Art Recovery (HEAR) Act of 2016, legislation designed to assist families seeking restitution for cultural property lost during the Holocaust. The heirs are also seeking to recover profits Sompo earned when the painting was exhibited in Chicago in Van Gogh and Gauguin: The Studio of the South.

In court, their lawyer, Thomas Hamilton, described the situation as a “devil’s bargain,” arguing that Sompo profited from art obtained through persecution. The heirs’ submission also drew on the 2009 Terezin Declaration, an international agreement signed by 46 countries to support the return of Nazi-looted art. They argue that the HEAR Act embodies this diplomatic commitment and obliges American courts to resolve such claims “expeditiously and fairly”.

The family further maintains that Sompo’s office in Chicago establishes sufficient ties to Illinois to allow the case to proceed there, countering the lower court’s dismissal on jurisdictional grounds.

Sompo’s legal team, however, insists the claim is unfounded. Daniel Graham, counsel for the insurer, told the court that because Mendelssohn-Bartholdy sold the painting at auction, it does not qualify as “Nazi-confiscated art”. He also argued that the heirs had misinterpreted the HEAR Act, which he said merely lifts statutes of limitation rather than creating new legal rights to sue.

Hamilton rejected that interpretation, contending that the act reflects broader foreign policy commitments of the United States. He dismissed arguments about the Terezin Declaration’s non-binding nature as a red herring.

The court has not yet indicated when it will issue its ruling. For the heirs of Mendelssohn-Bartholdy, however, the case has become not only a fight over a painting of extraordinary value but also a test of international pledges to confront the legacy of Nazi looting.