A Marseille fan known as 'William' attended the game and spoke to RMC Sport.
"We were in the group of Marseille fans after being welcomed by Guimaraes," he said. "When we warmed up, we started to [turn up the] heat on Patrice Evra because it's been several games that he is not good."
William claimed a stray shot from Evra then struck a fan on the head during the warm up and alleged Evra hurled insults after he was subjected to 'vulgar' chants.
"We warmed it up a bit," the fan added. "I will not say the words because it's a little vulgar but he responded.
"So obviously, we, the Marseille fans, we are a little hot. It does not excuse the behaviour of the supporter but it excuses even less the gesture of Patrice Evra to kick him in the head."
Meanwhile, L'Equipe reports OM supporters yelled 'Get out of Marseille, you're bad' and 'Go back to your videos' at Evra before the amazing flashpoint.