Detlev G. attended Tuesday's hearing at the Dresden regional court but did not address the courtroom.
The 58-year-old was last year sentenced to eight-and-half years in prison, having been convicted of committing a sexually motivated murder and interfering with a dead body.
However, Germany's top criminal court, the Bundesgerichtshof, overturned the verdict, arguing that the regional court had failed to sufficiently consider the defense argument that the victim had actually killed himself through strangulation.
It also said that the sentence imposed had been too lenient for a murder conviction.
Lawyers for the accused on Tuesday said Polish-born S. Wojciech hanged himself in the cellar at G.'s countryside retreat. At the time, the accused was said to have been upstairs drinking coffee. The legal team said that their client had been pressured to indulge his guest's "belief in reincarnation and medical curiosity."
A desire to be eaten
What is not in contention is that G. dismembered the body with a knife and saw, burying the pieces in his garden. A gruesome 50-minute video of the dismemberment was recorded and shown at the previous trial, in which a blood-soaked Detlev G muttered: "I never thought I would sink so low."
The defense say S. willingly visited the 57-year-old former policeman's home, a bed and breakfast inn in the mountain town of Hartmannsdorf-Reichenau, near the Czech border.
S., a 59-year-old businessman from Hanover, was said to have contacted the accused online, on a cannibalism site that boasted more than 30,000 registered members.
While S. dreamt of being killed and eaten, the court heard, G. dreamt of being a cannibal. However, there was no evidence that body parts were eventually eaten.
In a written dialog with G., S. was said to have expressed a desire to be "slaughtered" when the pair met.
According to the defense, G. backed out of the planned scenario as the pair traveled to the remote retreat. Other chat partners of the accused also testified that he had backed out of arranged plans when they traveled to meet him.
rc/msh (AFP, AP, dpa)