Flechtheim was driven out of Germany by the Nazis—and many works from his galleries are now in private collections and museums around the world. A lawsuit brought by his heirs raises questions about provenance:

“Works in the MoMA online database today with Flechtheim in their provenance histories were sold prior to 1933, meaning they are legally deemed to have been acquired absent any Nazi persecution, though, as Mr. Dascher put it, ‘Flechtheim was confronted with anti-Semitism already before 1933, even as a German officer during World War I.’ Museums around the world that now possess works the Nazis sold off can and do claim that they have them legally, even though some of the art may have come through galleries like Flechtheim’s, shuttered under anti-Semitic persecution.”