Judges in the western city of Mannheim sentenced lawyer Sylvia Stolz to three and a half years in prison on charges that include inciting racial hatred, and barred her from practicing law for five years, a court spokeswoman said.
Stolz made the remarks in 2006 while representing "historian" Ernst Zündel, who was handed a five-year prison term in Germany last February for repeatedly disputing the Holocaust as a historical fact.
The 44-year-old also signed a motion during Zündel's trial with "Heil Hitler" and shouted that the lay judges deserved the death penalty for "offering succour to the enemy" -- leading the court to dismiss her.
But Stolz refused to leave Zündel, with whom she has also been romantically linked for several years, and had to be forcibly carried out of the courtroom.
She was immediately taken into custody after Monday's verdict to avert further outbursts.
Born in Germany, Zündel lived in Canada for decades but fell foul of authorities there for his publishing empire built on anti-Semitic and neo-Nazi works. He was extradited to Germany in 2005.
Nazi Germany systematically murdered some six million European Jews during the war. It is a crime to deny the Holocaust in many European countries, including Germany and Austria.