Horst Mahler, who in the 1970s co-founded the extremist far-left Red Army Faction (RAF) and who later swung violently far-right, said he would appeal against the ruling.
The 72-year-old lawyer has a string of convictions for similar offences as well as for crimes dating back to his time with the RAF, which carried out a bloody campaign against the West German government.
He made the latest salute and comments during an interview for Vanity Fair with Michel Friedman, a former top figure in Germany's Jewish community who testified in the trial. Mahler has praised the September 11, 2001 attacks on the United States and has accused Jews of seeking "world domination."