Authorities say Belgacem, a 39-year-old Frenchman, had a long criminal record of drug and robbery offenses and spent 15 years in prison.
Two other soldiers shot and killed Belgacem before he could fire the rifle, the prosecutor said. Then, 90 minutes later, he attacked the military patrol at Orly, causing panic and the shutdown of the French capital's second-biggest airport.
The incident took less than three minutes, and no one at the airport was injured, officials said. He drank. But under the effects of alcohol and cannabis, this is where one ends up'.
Autopsy toxicology tests found traces of cocaine and cannabis in Belgacem's blood, according to the Paris prosecutors' office. After spending Friday night in a bar with his cousin, Ben Belgacem was pulled over by police for speeding in the gritty northern Paris suburb of Garges-les-Gonesse, where he lived, just before 7:00 am.
Earlier Saturday, in Garges-lès-Gonesse to the north of Paris, Belgacem fired a pellet gun at a police officer, who suffered minor injuries, during a traffic stop, officials said.
The man identified as Belgacem's father said on Europe 1: "He called me at seven, eight in the morning and said: "There you go, Papa".More news: Twitter hails fearless and progressive Sesame Street for new autistic Muppet Julia
Ben Belgacem also sprayed shots around a bar before hijacking another auto but - again - nobody was injured by the pellets. He told me, "I ask for your forgiveness".
He also had 0.93 grams of alcohol per litre of blood when he died, almost twice the legal limit for driving in France. "I've screwed up with a police officer".
Prosecutor Francois Molins said a Koran was found on Belgacem's body, adding cocaine was discovered during a search of the suspect's residence.
Belgacem's house was among scores searched in November 2015 in the aftermath of the suicide bomb-and-gun attacks that killed 130 people in Paris.
It is reported that in the seconds before his death, the attacker shouted that he was there to "die for Allah".
After the incident, the attacker is then believed to have stolen a auto to make his getaway before he headed to the airport. In mid-February, a machete-wielding Egyptian man attacked a soldier outside Paris's Louvre museum, injuring him slightly, before being shot and wounded.