Lille: Local authorities announced on Wednesday several investigations had been opened after the pitch invasion during the Ligue 1 game between Lens and Lille, including for "inciting hatred" and "sexual exhibition".
Dozens of Lens supporters stormed the Stade Bollaert-Delelis pitch at half-time on Saturday to confront the visiting Lille fans stationed in a corner of the ground after tensions flared with other spectators.
Riot police intervened to separate the factions of opposing supporters as both sets of fans hurled seats at each other over a partition fence.
Six people sustained minor injuries and police made two arrests.
A 26-year-old Lille supporter appeared in court Monday charged with "violence against a person holding public authority".
The hearing was postponed until 18 October and the man was released under judicial supervision.
Another inquiry is looking into "acts of inciting hatred and display of racist or xenophobic signs", the Bethune public prosecutor's department told AFP.
After the match a photograph circulated in the media and social networks showing a man purportedly making a Nazi salute.
Authorities are also investigating "events considered sexual exhibition" after a supporter was pictured, according to witnesses, exposing himself to a section of Lens fans, including a number of families.