The Katzenberger Trial was a notorious Nazi show trial. A Jewish businessman and leading member of the Nuremberg Jewish community, Lehmann (Leo) Katzenberger, was accused of having an affair with a young "Aryan" woman, and on 14 March 1942 was sentenced to death. The presiding judge at the trial, Oswald Rothaug, was later tried at the Nuremberg trials (see Judges' Trial) and sentenced to life imprisonment. The Katzenberger Trial later formed the basis of a subplot in the 1961 film Judgment at Nuremberg.
Together with his two brothers, Leo Katzenberger (born 28 November 1873 in Maßbach near Bad Kissingen) owned a large shoe wholesale shop as well as some thirty shoe shops throughout southern Germany. He was a leading member of the Nuremberg Jewish community, and from 1939 was chairman of the Nuremberg Jewish Cultural Organization. He had a long-standing friendship with a young photographer, Irene Seiler (née Scheffler), who rented rooms in an apartment house the Katzenbergers owned and which was situated next to the firm's offices. Local gossips had for years claimed that Seiler and Katzenberger were having an affair.
Someone denounced Katzenberger to the authorities and he was arrested on 18 March 1941 under the so-called Rassenschutzgesetz, or Racial Protection Law, one of the Nuremberg Laws, which made it a criminal offence as Rassenschande ("racial defilement") which prohibited Aryans from having sexual relations with Jews. Leo Katzenberger consistently denied the charges, as did Irene Seiler, who claimed the relationship between them was that of a father and daughter. The investigating judge initially concluded there was too little evidence to proceed with the case.
The investigation had however attracted the attention of Oswald Rothaug, a judge known for his severity and fervent support for Nazism, who arranged for the case to be brought to him. He recognised the publicity such a trial would generate and saw it as a way to display his Nazi credentials and further his career. He sent out tickets for the trial to all the prominent Nazis in Nuremberg.
No conclusive evidence was presented during the trial that Katzenberger and Seiler had ever had an affair (Seiler had been Katzenberger's tenant since 1932), let alone that it had continued up until and during the war. The law at the time did not call for the death sentence for breaking the Rassenschutzgesetz. The normal sentence would have been a term of imprisonment of several years. However, the Volkschädlingsgesetz, a wartime law, allowed capital punishment if one made use of wartime regulations such as the blackout to commit a crime. Based on a single eyewitness account that Katzenberger had been seen leaving the Seiler apartment "when it was already dark", Rothaug applied this law to pass a death sentence against Katzenberger.
Leo Katzenberger was guillotined at Stadelheim Prison in Munich on 2 June 1942. Irene Seiler was found guilty of perjury for denying an affair had taken place and sentenced to two years' imprisonment—in accordance with Hitler's wishes, women were not charged under the Racial Protection Law, but could be charged with perjury or obstruction of justice.
Even among some Nazi officials, the tenuous grounds on which Katzenberger had been sentenced to death caused disquiet. Oswald Rothaug was moved to a state attorney's job in Berlin in 1943 because the Justice Minister, Otto Georg Thierack, considered him unfit to be a judge. In 1947 he was placed on trial by the Americans, partly for his role in the Katzenberger trial, and sentenced to life imprisonment. He was released in December 1956, aged 59, and died in Cologne in 1967.