The father of Biarritz number eight Imanol Harinordoquy invaded the pitch and tried to punch a Bayonne player in the face in a bid to protect his son during a brawl in Tuesday's Top 14 Basque derby.
Lucien Harinordoquy walked onto the pitch in the sixth minute and tried to hit Jean Jo Marmouyet when a fight broke out between his son, who plays for France, and a pair of Bayonne players.
However, before he was able to strike Marmouyet he was tackled to the ground by Bayonne fly-half Benjamin Boyet.
Christian Gajan, director of rugby at Bayonne, criticised the actions of Harinordoquy senior following Biarritz's 21-19 win.
"I found this behaviour deplorable when he came to defend his son early in the match," Gajan told L'Equipe.
"This is an outrageous act."
Bayonne president Michel Cacouault also condemned the incident and revealed the club plans to lodge a complaint.
"It is intolerable. The club will lodge a complaint against M Harinordoquy," he said.
The father of the France back-row forward insisted he would make an official statement to apologise for his actions.