Adolf Hitler became chancellor of Germany on January 30... Many artists and intellectuals left Berlin immediately following the Reichstag fire, which Hitler blamed on the Communists, and which the Nazis used to whip up public furor... [Film producer] Seymour Nebenzahl was Jewish; so was Erich Pommer, as was widely known. ("Pure Jewish--everyone knew that," in the words of Conrad von Molo.) These two were scarcely alone. The Nazis ascribed Jewish lineage to a majority of motion picture figures, from the obscure to the most illustruous people. A Nazi Party tabulation in 1932, quoted by Helmut Heiber in his Goebbels biography, claimed Germany's motion picture distribution companies were 81 percent Jewish-run, with 41 percent of the scenarists, 45 percent of the composers, and 47 percent of the directors classified as Jewish, according to the Nazi racial arithmetic.McGilligan, pages 172-173:
...According to some accounts, Goebbels took Lang aside after this conference for a few words, sotto voce. That is how Lang himself told the story sometimes, and it is conceivable that Goebbels did whisper to the monocled director that he wanted him to come and speak to him in private about Das Testament...
Lang sometimes told it the other way around. According to Curt Riess, producer Seymour Nebenzahl, anticipating the blow of censorship, had asked Lang, against his own better judgment, to have a word with Goebbels. "His producer, who happened to be Jewish, had asked him to," wrote Riess, "because one of the first things Goebbels did was ban Das Testament des Dr. Mabuse. The producer was sure that Lang would be able to get that ban lifted. Lang's conversation with Goebbels took a different turn."
...On the following day... the German Board of Film Censors announced that Das Testament des Dr. Mabuse had been banned from exhibition. The only reason given was that the film posed "a threat to law and order and public safety--in accordance with a regulation to be found in the Law of Censorship," noted Gosta Werner in Film Quarterly.
...According to Harold Nebenzal, his father [the film's producer, Seymour Nebenzahl] was an early and fervent anti-Nazi who in the early 1930s was already warning his Jewish friends to heed the ominous threats of Goebbels and the demagogic Gauleiter Julius Streicher and liquidate their businesses. Seymour Nebenzahl was under no passport restrictions because he was not a German citizen; fearing what was about to happen under Goebbels, according to his son, the producer loaded the negative of Das Testament into the trunk of his Mercedes with Dutch license plates and drove it across the border.