The controversial Barton has been on his best behaviour since he made his Ligue 1 debut last November after serving out a 12-match ban for violent conduct in QPR's final Premier League match of last season against Manchester City.
The 30-year-old was back in trouble on Sunday, however, when he picked up two bookings in four minutes for rough tackles on Nancy players just before the hour mark.
Barton, who had received just two yellow cards in his 10 previous French league games, took to Twitter to accuse his opponents of exaggerating the contact to have him dismissed.
"Two very harsh yellows. First one wasn't even a foul," Barton tweeted. "Players who roll around when nobody touches them should be subsequently banned. I hate cheats. Authorities should address it."
Barton was not alone in his view and Marseille coach Elie Baup told a post-match news conference that he thought Barton's dismissal "unfair".
Barton will be suspended for Marseille's trip to lowly Evian Thonon Gaillard next weekend but could face a tougher sanction if summoned by the discipline commission.
However, Premier League fans will recall a similar incident last season when Barton himself was accused of feigning injury.
Salif Sane scored the winner for Nancy after Andre Ayew deflected the ball into his own net following a corner in the 75th minute, giving the visitors their first away victory of the season and lifting them to 19th, four points from safety.
The action-packed second half proved to be a nightmare for title-chasing Lyon, for whom Bafetimbi Gomis missed a chance to make it 2-2 from the penalty spot with three minutes to go and centre back Dejan Lovren was sent off in stoppage time.
Mutu, who put his side ahead with a close-range header in the 65th minute, netted the resulting penalty to seal the home team's victory.