In the western city of Lorient, the French navy has launched an investigation following claims that off-duty army officers tackled rioters during the protests in the country.

According to the Le Télégramme newspaper, which published some pictures of the proclaimed "anti-rioters" group, the marines wore hoods and masks while they beat up and apprehended protesters.

An interview with a 25-year-old man from the "anti-rioters" group, conducted by Ouest France, showed that the group was made up of approximately 30 off-duty marines, all of whom decided to “not leave the country to burn”.

The Defense Ministry, in turn, announced that the Forfusco navy unit based in Lorient has “opened an inquiry which is underway. Until the results are known, there will be no further comment."

On the other hand, Fabrice Loher, Lorient's mayor, told AFP that he could not confirm such information regarding the "anti-rioter" group but underscored having “seen people in masks. We thought they were rioters.”

Loher stressed that “what is important to me is what the Forfusco says,” noting that this might largely impact his town's reputation.

Le Telegramme also cited an anonymous officer underscoring that the police initially allowed the “anti-rioters” to intervene “because it was helping us” however, they later realized “they were going at it a bit too strongly”.

Paris puts youth accused of misconduct during protests on hasty trials

France has begun a judicial crackdown on individuals arrested during the nationwide protests and launched speedy trials for thousands of youths that took the streets following the killing of a teenager by the police.

Nahel Merzouk, a 17-year-old of Algerian and Moroccan origin was shot in the chest at point-blank range last week in the western region of Paris after he was pulled over for breaking traffic rules in a yellow Mercedes.

"Very clearly, I want a firm hand,” French Justice Minister Eric Dupond-Moretti told judges in a message aired on France Inter radio on Monday.

It is yet unclear to what extent Paris is willing to go to suppress youth demonstrating against the killing of teenager Nahel Merzouk, but President Emmanuel Macron called on the French government to consider a social media blackout and expanded control over uploaded content in case the situation "gets out of hand".

“We need to think about how young people use social networks … when things get out of hand, we may have to regulate them or cut them off," Macron told 200 mayors on Wednesday, whose municipalities witnessed angry protests.

“I think it’s a real debate that we need to have in the cold light of day."

Official figures suggest that between 3400-4000 people have been arrested so far, including around 1,200 minors - some even as young as 12. Most of the arrested individuals have no previous criminal record, the justice ministry said.

Special sessions were held over the weekend in the area where Merzouk was killed, while other courts across the country launched hasty trials and have been working around the clock to prosecute suspects.

Read more: France opts for shutting down, censoring social media over protests