German state prosecutors have lodged an appeal against the manslaughter verdict handed down to self-confessed cannibal Armin Meiwes.
Meiwes' lawyer said his client was "happy" at being cleared of murder
Meiwes was jailed for eight-and-a-half years for killing and partially eating a man he met on the Internet.
During the trial, the prosecution argued for a murder conviction which carries a 15-year jail sentence.
But the court rejected the argument on the grounds that Meiwes had followed his victim's instructions.
A spokesman for the state prosecutor's office said it was sticking to its original position. No date has been set for a hearing.
According to AFP news agency, defence lawyer Harald Ermel said he was considering whether to lodge his own appeal.
The defence had sought a verdict of illegal euthanasia, carrying a far shorter sentence of six months to five years, on the grounds that it had been a "killing on request".
Meiwes killed and ate Bernd Juergen Brandes three years ago, after placing an advert on the Internet.
He told the court in Kassel that it was the realisation of a dream he had had since his school days - when he fantasised about consuming classmates.
Despite this, psychologists said he was mentally fit to stand trial.