The Benalla affair, as it is known in France, was the first major scandal of Macron's presidency, coming just a year after the centrist president's election on a promise to restore integrity to French public life.
A former nightclub bouncer who had a senior security role in Macron's team, Alexandre Benalla was caught on video striking a young man and grabbing a young woman by the neck at a May Day protest in Paris in 2018.
He had been given leave by the presidency to attend the protest as an observer but, once there, waded into the fray wearing a police helmet and began roughing up leftist demonstrators.
The presidency initially held off reporting Benalla to the authorities, leading to allegations of a cover-up.
He was fired only after Le Monde newspaper revealed details of the story in July 2018.
Senate noted 'major flaws' in government handling of case
A French Senate commission of inquiry found "major flaws" in the government's handling of the affair and said it suspected Macron's aides of trying to cover up some of the facts.
Judicial sources confirmed on Tuesday that he would be tried for assault, "unauthorised interference in the performance of public duties" and using unauthorised insignia, the last charge relating to Benalla's wearing of a police helmet.
Benalla claims he was helping police arrest the protesters.
He has already been ordered to stand trial in another case, involving his continued use of diplomatic passports after his dismissal.
