French President Emmanuel Macron came under fire Thursday after his aide Alexandre Benalla was caught on tape striking protester, but did not inform law enforcement authorities.

Benalla was suspended hours after the video was shared by local news outlets. Later in the day French Interior Minister Gerard Collomb said the actions of Macron's aid were "unacceptable."

A video from a May Day rally released by Le Monde newspaper showed a man wearing a police helmet and identification tag dragging a woman away and then striking a demonstrator. He was later recognized as a member of the French presidency staff.

One witness who saw the incident told the Guardian: “What I watched was not normal, it was extraordinary, it was not legal and it was not techniques used by the police. It’s unacceptable, I’m extremely angry and I want to see action by the justice system, police and administration against this member of staff of the presidency.”

Benalla, who has never been employed as a police officer but pretended to be one, had asked for permission to use a day off to “observe police operations” 

The Paris prosecutor, which was unaware of the matter before Thursday, launched a preliminary investigation against Alexandre Benalla on suspicion of violence, usurping the function of a police officer and using signs reserved for public authorities.

On a trip to southwestern France Thursday, Macron declined to answer questions from reporters on the subject.