Two first-half goals from Dimitri Payet gave Marseille a stormy 2-1 win over bitter rivals Lyon, who complained that their team bus was pelted with missiles on the way to the Stade Velodrome on Sunday.
The match, which saw Marseille go second in Ligue 1, was also interrupted for five minutes when a laser was shone at Lyon goalkeeper Anthony Lopes and again in the second half because of smoke caused by pyrotechnics.
Photographs showed windows on one side of the Lyon bus had been smashed and club president Jean-Michel Aulas at one point threatened to pull his team out of the match.
"We were victims of an ambush," Aulas told reporters. "If it continues like this, we will not play."
French media said that Lyon insisted on using their highly customised and distinctive team bus despite being advised to use a more discreet vehicle.
The match went ahead and there was more chaos after Marseille were awarded a penalty.
First, Marseille forward Dario Benedetto appeared to push another player, leading to a VAR review over a possible red card, and then a laser beam was shone towards Lopes.
Payet finally converted in the 18th minute, five minutes after the spot kick was awarded, as Marseille became the first team to score 4,000 goals in Ligue 1.
The Reunion Island-born player struck again in the 39th minute after he won a tackle in midfield, found Lopez, collected the return and drilled his shot past Lopes.
Marseille had Alvaro Gonzalez sent off five minutes later for a denying Dembele a clear scoring chance but the hosts held on to leave them with 22 points, eight behind leaders Paris Saint-Germain.