Mehdi Nemmouche was convicted last week of "terrorist murder" for the anti-Semitic gun rampage in the Belgian capital in May 2014, a crime committed following his return from Syria's battlefields.
He was found to have killed the four victims in less than 90 seconds, shooting them with a handgun and a Kalashnikov rifle with what one paramedic who attended the scene called "surgical" precision.
The court, which handed down the sentence in the early hours of Tuesday morning, said the 33-year-old had shown no regret for the killings and simply replied "life goes on".
"Mr Nemmouche, you are just a coward, you kill people by shooting them from behind, you kill old women by shooting them with an assault rifle, you kill because it gives you pleasure to kill," prosecutor Yves Moreau had said.
Urging the jury to take a firm line, Moreau said: "If you say that in Belgium one can be a terrorist without being punished very severely, then we must not be surprised to see people arrive in this country with bombs or assault rifles in their suitcases."
Nacer Bendrer, who was found guilty of being the co-author of the attack for supplying the weapons Nemmouche used, was handed a jail sentence of 15 years.
Bendrer, who is also French, said he was ashamed that he had ever met Nemmouche, saying "he's not even a man, he's a monster".
The pair, who have 15 days to lodge an appeal, will both serve their sentences in France.
Nemmouche will also face another trial at a later date over his role as a jailer to four French journalists taken hostage by jihadists in Aleppo in 2013.
Two of the journalists who traveled to the court to give evidence both said they had "no doubt" it was him.