In November 2007, Mahler admitted to distributing an outlawed book by Holocaust-denier Germar Rudolf, called “Lectures on the Holocaust.” Mahler, 70, also distributed discs of himself giving a speech that called the Holocaust the “most momentous lie in world history.”

His defence attorney plans to take the case to the country’s high court to question the definition of incitement of hatred (Volksverhetzung) in the German penal code.

Before he started supporting the neo-Nazi National Democratic Party (NPD) in 2000, Mahler was a member of the left-wing Red Army Faction terrorist group in the 1970s. He also defended several of the RAF’s members during criminal trials.

He was sentenced to 14 years in prison for his criminal activities as part of the group in 1970. He was released four years early in 1980 with help from lawyer Gerhard Schröder, who later became German chancellor in 1998.