A New York City art gallery refuses to return a portrait by Amedeo Modigliani (1884-1920) that a French man claims was his grandfather's until Nazis confiscated it during World War II. According to Courthouse News Service, Philippe Maestracci has sued the Helly Nahmad Gallery, seeking return of the 1918 Modigliani painting, "Seated Man With a Cane."

Maestracci says he is sole heir of Oscar Stettiner, a Jewish art dealer who owned a Paris art gallery, and the Modigliani painting, which he loaned in 1930 to the Venice Biennale.

In his federal complaint, Maestracci says that the Nazis had "a practice and policy of despoiling Jewish families of property located in the occupied zone by forced sales." When Stettiner fled Paris in 1939 "with the threat of Nazi invasion looming," his art collection was left behind.

In 1941, the Nazis appointed Marcel Philippon a temporary administrator to sell Stettiner's property, Maestracci says. On July 3, 1944, the Modigliani was sold without Stettiner's consent, and the painting could not be located after the war by Stettiner, who died in 1948, or his heirs, according to Maestracci.

The grandson says he located the Modigliani in 2008, when a Sotheby's catalog listed it as consigned for sale by the Helly Nahmad Gallery.

Maestracci claims he wrote to the gallery for the return of the painting, but he received no response. He says that under New York law, "the July 3, 1944 sale was void since it occurred without the owner's consent in violation of international law and New York's law and public policy not to recognize forced sales under the Nazi regime."