A 14-year-old teenager was shot dead and two other minors were injured on Wednesday evening on a housing estate in Marseille.
The two wounded children are aged 14 and 8.
The local prosecutor said that "it was a motorbike with two people armed with at least one assault rifle — Kalashnikov type — who fired (...) in the street."
The prosecutor's office did not say whether the minors were specifically targeted by the gunmen.
The incident took place on the Marronniers housing estate in Marseille's 14th district, one of the city's most deprived, at the entrance to a car park, residents told an AFP reporter on the spot on Thursday morning.
The investigation has been handed over to the judicial police.
"The judicial investigations are underway, but it seems fairly obvious that the war of territories to recover lucrative (drug) dealing points is probably one of the reasons for these armed attacks," Interior Minister Gerald Darmanin said at a press briefing on Thursday morning.
He stressed that these "absolutely unacceptable acts" show "the terror that is taking hold in neighbourhoods or housing estates that are known to be prey to drug traffickers."
Several homicides by gunfire have taken place in recent months in France's second-largest city in neighbourhoods affected by drug trafficking. Eleven people have officially died since the beginning of the year in score-settling attacks in the Bouches-du-Rhône department, according to figures from the police prefecture in mid-August.
"Some traffickers have gone abroad to escape the national police, others are in prison, people want to take their place, this probably explains it," Darmanin said.
"Beyond this despicable incident, over the last ten years, deaths by settling accounts have been halved in Marseille and I encourage the national police to continue their work to impose the republican rule over drug traffickers," he added.