Marseille defender Andre Ayew was racially abused by Nice fans during Sunday's south coast derby and two officials clashed before the match.
L'Equipe said on Monday that, despite pleas by Nice's director of security, Ayew, 23, was abused during his team's 1-0 victory, while press photographers were threatened and spat at by fans in the second half.
Before the game, home fans set off flares and homemade explosives as the Marseille team coach arrived.
The tone for the toxic atmosphere was set by a pitchside row between OM sporting director Jose Anigo and Nice director-general Julien Fournier before kick-off.
Anigo reportedly accused Fournier of getting Marseille supporters barred from the game after an Interior Ministry ruling on Thursday prohibited them from attending.
"Mr Anigo wanted to talk to Mr Fournier," Nice president Jean-Pierre Rivere told RMC radio. "What was said was perhaps misunderstood or misheard, and it just exploded. There's no excuse. They have their disagreements. I didn't ask for an apology.
"There is no place for that sort of altercation on a football pitch - it's unacceptable. We can talk things over in a normal way."
He said he would back Fournier if he decided to make a complaint to police, but added that he hoped the matter would not go any further.
"From my point of view, I can't hide the fact that I'm on very good terms with [OM president] Vincent Labrune and I don't want to get caught up in an interminable argument," he said.
"When there's a problem, we resolve it, draw a line under it and move on. You don't look back."
L'Equipe added that Anigo and Fournier had differences dating back to a spell working together at Marseille, where Fournier was general secretary before being relieved of his duties in 2009.