Biarritz have been summoned to a hearing by the disciplinary commission of the French National Rugby League (LNR) after the father of Biarritz captain Imanol Harinordoquy ran onto the pitch during yesterday's fiery Top 14 Basque derby with Bayonne.
Both clubs will also have to explain the series of punch-ups that littered the 100th derby which Biarritz won 21-19 with the last kick of the match for only their second win of the season.
However, it is the sixth-minute intrusion of Lucien Harinordoquy that the commission will examine the closest.
The incident could lead to Biarritz being fined up to a maximum of 46,000 euros ($NZ 79,000), as well as being barred from playing a maximum of two matches at home.
Harinordoquy's father - a cattle trader - had apologised earlier today for running onto the pitch to defend his son in a fight that erupted during yesterday's game.