The remanding in jail of a French police officer in Marseille created new controversy Monday, weeks after deadly protests, with a plea from police commanders for the officer's release inciting outrage on the left and anxiety inside the court system.

France was rocked by violent protests for nearly a week following the death of 17-year-old Nahel Merzouk by a police officer during a traffic stop outside Paris last month. The cop has been charged and imprisoned pending trial.

A probe was launched into six police officers in Marseille after a 22-year-old restaurant worker, identified as Hedi, was found unconscious on the street due to being shot with “flash ball” rubber bullets and heavily beaten with a truncheon, which required him to reside in a hospital for several days.

Hedi told the French newspaper La Provence that after leaving a cafe near protest areas, a police force attacked him and his friend.

"Flash ball” rubber bullets used by the police to disperse demonstrations across France have been heavily criticized by human rights activists and organizations for their extremely harmful nature.

The bullets have so far caused the death of two individuals, while other victims were left suffering from brain injuries, eye loss, and broken bones, especially ribs.

Read more: Riot vs protest: The West's exploitation of media hegemony

Four police were charged last week over the incident, one of whom was remanded in custody ahead of trial. 

France's national police chief Frederic Veaux expressed in an interview for Le Parisien that he was unable to sleep knowing that the officer was in prison. "In general, I believe that ahead of a possible trial, a police officer should not be in prison, even if he may have committed serious faults or errors in the course of his work," Veaux claimed. 

His view was supported by the Paris police chief Laurent Nunez in a Tweet.

In an interview for French television, President Emmanuel Macron stated on Monday that although he understood how the police felt, "no one in the Republic is above the law."

The President did not directly respond to how he felt regarding Veaux's statements but stated that "it (the ruling to jail the policeman) is a decision which was taken by a judge so I am not going to comment on it."

An anonymous source from the police union told AFP that hundreds of officers have taken sick leave to protest the officer's imprisonment. 

Others responded to the call of the SGP Police Unit union and put themselves under so-called "code 562", which means that they only respond to emergency and essential missions.

But in a rare public intervention, Marseille's top judge Olivier Leurent in a statement urged "restraint so that the judiciary can pursue the investigation... free from pressure and in complete impartiality."

Hard-left France Unbowed (LFI) leader Jean-Luc Melenchon accused France's leaders of allowing police to "wage war" as they refuse to hold the police accountable for not respecting the law.

Socialist party leader Olivier Faure called it "extremely serious" that the police "places itself above justice and the rules of pre-trial detention," adding that democracy was at stake and that "Parliament must be reconvened urgently."

Before the death of Merzouk, the French police had been accused by opponents of institutional racism.

French prosecutors have also launched an inquiry into an internet fundraising campaign for the French police officer who murdered Nahel M., which earned more than 1.6 million euros ($1.7 million) before being closed in early July.

The cold-blooded murder of Merzouk in Paris suburbs has exposed deep division within French societies. The event sparked ablaze a fire that holds within it decades worth of resentment felt by minorities in the country toward authorities.

The protests have also angered the right in France who have been critical of Macron's government for its inability to deal with the situation, leading to clashes between white civilians.