A senior security adviser to French President Emmanuel Macron is under investigation for beating up protesters at a May Day demonstration.
Video footage from the protest shows Alexandre Benalla lifting a protester off the ground by his neck and covering his mouth before striking him over the head with his fist.
Benalla had been invited to observe the demonstrations alongside France's riot police for the protests on May 1 in Paris.
Government minister Julien Denormandie called Benalla's behavior "unacceptable" on Thursday.
Speaking to French radio Inter, Denormandie said: "He was invited as an observer and his behavior was unacceptable. He was sanctioned immediately for this. He was suspended and then given a different role."
A spokesperson for the Élysée Palace told CNN that Benalla was suspended for 15 days and would no longer be part of Macron's traveling security detail. The spokesperson also said this punishment was his "last warning" and that "next time" Benalla would be fired.
Activist Taha Bouhafs, who was demonstrating at the protest, captured the incident on his phone.
In an interview with French radio SUD Thursday, Bouhafs said the protest, which was organized in the capital's Latin Quarter, went from a "convivial" atmosphere to a violent one after riot police used tear gas on the crowd and began hitting people with batons.
Bouhafs said he had seen Benalla at various moments throughout the protest wearing a police armband and assumed he was a policeman or a member of special security forces. "I never thought he was someone who worked with Emmanuel Macron," Bouhafs said.
When the 21-year-old saw Benalla grab a woman by the neck and attack an already "neutralized" male protester, he decided to confront him on camera.
"He was very aggressive. There was no reason for this violence. The man was not dangerous, he was on the ground and begging him to stop. Everyone around him, me included, asked Alexandre Benalla to stop. I said, 'Stop! Stop!' Then he stopped and I got closer and filmed his face and said, 'Look at this face. He did this.' And then he fled."
Macron has yet to address the incident, avoiding a question from the media at a meeting he attended in the Dordogne region on Thursday.
Jean-Luc Mélenchon, leader of the far-left party France Unbowed described the event as "an affair of exceptional gravity."
"If we allow anyone to pretend to be a police officer alongside the police, then we are no longer living in a state of law," Mélenchon told reporters outside the National Assembly on Thursday.
"Why are we having a preliminary inquiry?" Mélenchon added. "All the elements are there to indicate an offense."
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