"I admit the stabbing, but I didn't mean to kill him," Denis Colnot, who imitates Serge Gainsbourg at karaoke sessions and talent contests in eastern France, told the court.
Colnot and Johnny Hallyday impersonator Michel Pacchiana - stage name Johnny Riviera - are bitter rivals, entering the same competitions and passing severe judgements on each others' artistic abilities.
Relations have not been improved by the fact that they live in the same block of flats in Epinal in the Vosges region.
In July 2011 Colnot saw Pacchiana mowing the lawn in front of the building where they both live, hurled insults at him from his balcony and then, grabbing a kitchen knife, ran down and stabbed him in the neck within millimetres of the carotid artery.
He could no longer bear his rival's sneers, he told police, explaining that Pacchiana had called him a "loser" and other insulting names.
Pacchiana claimed that Colnot, who has been in jail awaiting trial for two years, was simply fed up with continually losing the talent contests the two competed in.