AFP

PARIS - More than 700 people have been sentenced to prison over riots in France late last month, the country's justice minister said Wednesday while lauding the fast-track trials that have alarmed some defence lawyers.

In total, 1,278 verdicts have been handed down, with over 95 percent of defendants convicted on a range of charges from vandalism, theft, arson or attacking police officers.

Although minor prison terms can usually be converted into a non-custodial punishment -- usually the wearing of an electronic bracelet -- around six hundred people have already been jailed, Justice Minister Eric Dupond-Moretti said.

"It was extremely important to have a response that was firm and systematic," he told RTL radio. "It was essential that we reestablish national order."

The most intense urban violence in France since 2005 began on June 27 after a police officer shot dead a 17-year-old French-Algerian boy during a traffic stop west of Paris, in an incident recorded by a passerby.

The riots were contained after four nights of serious clashes thanks to the deployment of around 45,000 security forces, including elite police special forces and armoured vehicles.

Dupond-Moretti had led calls for courts to hand down harsh sentences as a deterrent, with some staying open over the weekend during the clashes to handle a backlog of cases.

Many suspects faced immediate appearances under a fast-track system that has raised concerns about the fairness of the judicial process and the heavy sentences for sometimes first offenders.

A message that reads 'No justice, no peace' is seen amongst other messages and flowers brought by people for the slain 17-year-old teenage boy Nahel M. at the site where he was shot by police, in the Paris suburb of Nanterre.

The average age of the over 3,700 people arrested was just 17, with the minors appearing in separate children's courts.

Interior Minister Gerald Darmanin said that around 60 percent of those arrested had no previous criminal record.

Snapchat crackdown

Facing widespread shock and anger over the destruction, the government has also encouraged police and prosecutors to investigate people who had used social media such as Snapchat to encourage or organise rioting.

Last week, a 38-year-old man from a suburb of Lyon was sentenced to one year in prison after being found guilty of public incitement of crime with messages on Snapchat.

Dupond-Moretti said it was important to "remind young people that Snapchat is not a hide-out" and if they use it to organise a crime "we can find them."

President Emmanuel Macron told a meeting of mayors that it might be necessary in the future to "cut off" social media during major civil unrest, but ministers later said the idea was not under active consideration.

The government has floated the idea of new legislation to enable the state to fine parents whose children take part in rioting.

Existing legislation means parents can already be prosecuted for "compromising the health, security, morality and education of their child" by failing to uphold their legal obligations.

Dupond-Moretti said some parents would be pursued over the riots, but on a case-by-case basis.

"It's not about punishing the mother who works at night and is bringing up her child on her own," he said.

Around 23,000 fires were lit during the riots, 273 buildings belonging to the security forces were damaged, along with 168 schools and 105 mayor's offices, according to a provisional tally from the interior ministry.

Elsewhere, prosecutors in the western city of Lorient said Tuesday they had opened an enquiry into claims that a group of young men, possibly marine commandoes from a nearby military base, helped police detain rioters.

The number of people sentenced to prison over the latest riots exceeds the number after the 2005 unrest when around 400 people were sent to jail.