The policeman accused of shooting Nahel in Nanterre was charged with voluntary homicide and remanded in custody, but it remained to be seen what impact that may have on the unrest.
France has been hit by protests after the teen, named "Nahel M," was shot point-blank Tuesday during a traffic stop captured on video that has unleashed rage and reignited debate about police tactics.
"The whole world must see that when we march for Nahel, we march for all those who were not filmed," activist Assa Traore, whose brother died after being arrested in 2016, told the rally led by the teenager's mother.
Some 40,000 police have been mobilised to try to keep the peace on Thursday, more than four times Wednesday's numbers on the ground when dozens were arrested.
Cars and bins were torched Wednesday night in parts of the country, while some 150 people were arrested nationwide following clashes and unrest that left a tramway's carriages on fire in a Paris suburb.
President Emmanuel Macron on Thursday urged calm after the angry protests.
Branding the overnight clashes "unjustifiable," Macron told a crisis meeting of ministers that the coming hours and an afternoon march in memory of Nahel in Nanterre should be marked by "contemplation and respect."
"The last few hours have been marked by scenes of violence against police stations, but also schools and town halls... against institutions and the Republic," he said.
"We are sick of being treated like this. This is for Nahel, we are Nahel," said two young men calling themselves "Avengers" as they wheeled rubbish bins from a nearby estate to add to a burning barricade in the capital.
In Nanterre, France, the local prosecutor said Thursday that the use of a firearm by a policeman who killed a French teen this week did not meet the legal conditions under which such force can be used.
Pascal Prache, state prosector in the area where the killing took place, also said that the policeman was being taken before a magistrate on Thursday with a view to charging him with homicide, and added he was demanding the officer remain in custody.