French President Emmanuel Macron was strongly criticised after his office suspended one of his aides, Alexandre Benalla, who was caught on camera striking a May Day protester but did not inform law enforcement authorities.
Benalla was suspended hours after the video was shared by local news outlets.
"Someone was found to have unacceptable behaviour and there was a sanction", Social Cohesion Minister Julien Denormandie said on France Inter radio on Thursday.
The clip, released by newspaper Le Monde yesterday, also showed Mr Benalla dragging a woman from the demonstration.
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".
On a trip to southwestern France Thursday, Macron declined to answer questions from reporters on the subject.
A short time later, the man identified as Benalla is seen grabbing a young man around the neck, repeatedly hitting him and even stomping on his stomach.
Despite his official change to a desk job, Benalla was seen this month on the ground with police at several high-profile events, including the return home Monday of France's champion World Cup team, an event attended by hundreds of thousands.
Roger-Petit said the punishment dealt out to Benalla was the "most serious" ever given to a top aide at the presidential Elysee Palace and served as a "last warning before dismissal".
Roger-Petit, the presidential spokesman, stressed that Benalla had requested authorization to use his day off "to observe" security forces' operations on May Day when marches are traditionally held.
Opposition parties condemned the presidency's handling of the matter, arguing the punishment was too lenient and that the incident should have been referred promptly to judicial authorities.
A parliamentary inquiry into the case has also been opened. "This man is the eyes and ears of the prince (Mr Macron)".
"This video is shocking".
The 40-year-old centrist was in Australia on May 1, a traditional day of demonstrations in France organised by trade unions, but which was marred this year by hundreds of black-clad anarchists who clashed with police and smashed up shops.