Islam Times reports from AP: A court in the Bavarian city of Regensburg found Williamson guilty of incitement for saying in a 2008 interview with Swedish television that he did not believe Jews were killed in gas chambers during World War II.
The court ordered Williamson to pay a fine of euro10,000 ($13,544).
The Roman Catholic bishop was barred by his order from attending Friday's proceedings or making statements to the media.
His lawyer, Matthias Lossmann, told The Associated Press after the court ruling that Williamson has yet to decide whether he would appeal.
Denying the Holocaust is a criminal offense in Germany.
The court ordered a fine of euro12,000 for Williamson last year, without a trial. But the bishop appealed, forcing his case to be tried publicly.
Lossmann said that Williamson had explicitly asked the Swedish television crew conducting the interview not to broadcast it in Germany.
In issuing her ruling, Judge Karin Frahm said the bishop could not have expected that the clip would show up on YouTube and be seen directly in Germany, and that led her to reduce the fine, court spokesman Bernhard Schneider told the AP.
The journalists who conducted the interview ignored a court order to attend the trial, Lossmann said, leaving the judge to rely on written statements as testimony.
"That does not do a case like this justice," Lossmann said.
The interview was conducted near Regensburg and was granted shortly before Williamson's excommunication was lifted by Pope Benedict XVI, along with that of three other bishops from the anti-modernization movement of the late Archbishop Marcel Lefebvre.
The American Gathering of Holocaust Survivors said in a statement it welcomed the ruling as "a symbol of modern German determination to prohibit the dissemination of Holocaust denial on its soil."
The U.S.-based group's vice president, Elan Steinberg, called Williamson's remarks vile and craven and called upon his order and the Vatican to cut all ties with him.
The lifting of Williamson's excommunication sparked outrage among Jewish groups and in Israel. The Vatican's handling of the affair prompted criticism from German Chancellor Angela Merkel.
Six million Jews were killed during the Nazi Holocaust, many of them murdered in gas chambers.
Williamson lives in Britain.