The French government announced on Wednesday that 31 people were arrested and security was heightened after riots in a Paris suburb.

Protesters and police clashed overnight in the Paris suburb of Nanterre where a 17-year-old delivery driver was shot and killed by a police officer.

French President Emmanuel Macron said the shooting was "inexplicable" and "unforgivable."

"Nothing, nothing justifies the death of a young person," Macron said, expressing his "respect and affection" for the victim's family.

France's National Assembly observed a minute of silence for the teenager on Wednesday afternoon.

What we know about the unrest in Paris

Angered by the shooting death, demonstrators set barricades on fire, while police fired tear gas.

The officer accused of firing on the driver has been detained on homicide charges, the Nanterre prosecutors' office said.

Interior Minister Gerald Darmanin said that the police supervisory body (IPGN) launched an internal investigation into the incident.

The violence, which began on Tuesday evening with a demonstration outside the Nanterre police station, spread to neighboring towns.

In Mantes-la-Jolie, a town hall was set ablaze. Police used tear gas and rubber bullets but soon had to retreat.

Darmanin said 25 police officers were injured and 40 cars burned in the overnight unrest, mostly in Nanterre.

He said 1,200 police were deployed overnight and 2,000 would be out in force Wednesday in the Paris region and around other big cities to "maintain order."

What triggered the protests?

The protests were sparked by a video posted on social media of Tuesday's shooting incident.

In the video, which several French news outlets have verified, two police officers can be seen trying to stop a vehicle, and one is pointing his weapon at the driver through the window and firing at point blank when he drives off.

The car moved a few dozen meters before crashing.

Lawyers representing the family of the young driver rejected police assertions that the officers' lives were in danger because the driver had threatened to run them over.

A passenger who was in the car was briefly detained and then released. Police are searching for another passenger who fled.

Political reactions to the incident

Prime Minister Elisabeth Borne tweeted that she hoped "our absolute demand for the truth will allow calm to prevail over anger."

She also told parliament that the police action "was manifestly not in line with the rules of engagement for police."

Jean-Luc Melenchon, a left-wing politician, said that the police were bringing the authority of the state into disrepute and needed to be reformed from the ground up.

"The death penalty no longer exists in France. No police officer has the right to kill except in self-defense," he tweeted.

Meanwhile, Eric Ciotti, the president of the conservative Republicains, expressed his support for the police.

Ciotti called the police "defenders of our collective security," and referred to the protest while tweeting that "Nothing justifies this chaos!"

Deadly use of firearms is less common in France than in the US.

fb, ns/lo (dpa, AP, AFP)