Detlev Günzel, 58, had cut the body into small pieces in a slaughter chamber he built in his cellar, before burying them in his garden. There was no evidence that he ate any part of his victim.
He was last year already given a slightly shorter sentence - eight and a half years - for killing Polish-born Wojciech Stempniewicz in 2013.
But the Federal Court of Justice had overturned the first verdict which it deemed too lenient for a murder conviction.
Following a new trial that began early November, a regional court in the eastern city of Dresden agreed with the initial verdict not to impose the maximum 15-year sentence because the victim had a death wish.
It sentenced Günzel to eight years and seven months. The verdict is subject to appeal.
Günzel, a three-decade veteran of the police force, had met Stempniewicz in October 2013 on a website for slaughter and cannibalism fantasies billed as the "#1 site for exotic meat" and boasting more than 3,000 registered members.
His defence team argued that Stempniewicz had hanged himself in Günzel's custom-designed "S&M studio" before Günzel took a knife, then an electric saw, to the gagged-and-bound man.
Soon after the death, Günzel admitted to detectives that he killed the victim by cutting his throat. But he later retracted his confession.
Investigators had testified in the first trial that they could not definitively determine the cause of death due to the state of the corpse.
Günzel and Stempniewicz had extensive contact online and by telephone before finally arranging the fatal date on November 4th 2013. Their emails bore the title "Schlachtfest", the German word for a country feast after the slaughter of a pig. Günzel called himself "Caligula 31", Stempniewicz logged on as "Heszla-Longpig".
A 50-minute video Günzel made was played during the trial and showed him at one point covered in blood as he mutilated the corpse, muttering, "I never thought I would sink so low."
The presiding judge at the first trial had said that the expression of faint regret seen in the video made it unlikely Günzel would repeat such an act.
She said this differed from the infamous case of German cannibal Armin Meiwes, who admitted to killing, mutilating and eating the flesh of a lover in 2001 after meeting him on the Internet via an advertisement looking for a "slaughter victim".