Once one of the world's most wanted fugitives, the assassin is already serving two life terms in France for attacks in the 1970s and 1980s.
A French court sentenced "Carlos the Jackal" to life imprisonment on Tuesday for a 1974 grenade attack on a Paris shop that killed two people and wounded 34 others.
Once one of the world's most wanted fugitives, he has been serving two life terms in France for attacks carried out in the 1970s and 1980s, when Europe was repeatedly targeted by groups sympathetic to the Palestinian cause.
Prosecutor Remi Crosson du Cormier had told the court in Paris on Monday that "all evidence gathered in this investigation points to Carlos."
Cormier, however, admitted that investigators had found no DNA, fingerprints or CCTV evidence from the grenade attack on a store in the French capital on September 15, 1974.
The flamboyant white-haired defendant, wearing a black shirt and jacket with a trademark kerchief in the breast pocket, blew kisses at supporters at the start of the hearing, taking the stand to denounce the "absurdity of a trial held 43 years after the fact."
Lawyers for the 67-year-old Venezuela native, whose real name is Ilich Ramirez Sanchez, had derided the two-week trial as "judicial palaeontology."
Defence lawyer Francis Vuillemin, calling for an acquittal, said a conviction would only feed the cult status of his client.
"If you convict him, he wins, if you acquit him, he loses," Vuillemin told the three-judge panel. "So acquit Carlos and he will take it out on his lawyers."
Carlos boasted at the start of the trial: "No one in the Palestinian resistance has executed more people than I have."
Carlos has been in prison in France since he was arrested by French elite police in the Sudanese capital Khartoum in 1994.