Three French policemen were beaten into a presidential candidate for allegedly assuming security recordings of an incident a protesters in May, French media reports.
This week, Alexandre Benalla was unmasked as the attacker who was shown on a video about a demonstrator's attack.
The officials are suspected of giving Mr. Benalla security pictures to prove his innocence, the reports say. 1
Interior Minister Gérard Collomb was summoned to answer questions in the National Assembly on Monday.
The three police officers arrested on Saturday are senior members of the Public Order Directorate in Paris, according to news agency AFP
. They were suspended on Friday.
What about Mr Benalla?
He was dismissed by the presidency. On Friday, President Emmanuel Macron's office said it had made the decision after "new facts" surfaced in the case.
Mr Benalla is interviewed for taking pictures of a woman and a man being beaten during the May Day protests
The video was released on social media at that time. But the case became a political scandal after the newspaper Le Monde had revealed that the assailant wearing a police helmet was Mr. Benalla.
A former bodyguard to Mr. Macron, he was hired as an advisor to the president's chief of staff after the Election last year.
Benalla is charged with attacks and turns out to be a police officer.
In May, a few days after the incident, he was suspended for two weeks, but the prosecutors were not reported.  Hugh Schofield of the BBC in Paris says this suggests that Mr. Macron's office may already have been aware of his actions.
What happened on May 1?
The incident took place in a popular tourist resort in the Latin Quarter of Paris, where about 100 people had gathered.
The original video shows a man wearing a police helmet but not in uniform joining the CRS riot police after clashes.
He grabs a woman by the neck and charges her down the street before both disappear from the camera.
Shortly thereafter, he returns to the scene and attacks another demonstrator who was briefly taken away by the police before he remains alone on the ground.
The man in the helmet can be seen, as he grabbed the young demonstrators around the neck, slaps him on the head and apparently stomps on his stomach as he falls to the ground.