Marseille's winless streak has stretched to 13 matches after a 2-1 defeat at Lorient.
The hosts were ahead at half time when Arnold Mvuemba fired in from the penalty spot following Jeremy Morel's foul on Joel Campbell.
They extended their advantage eight minutes after the break as Kevin Monnet-Paquet converted to finish off a quick counter attack.
The visitors gave themselves a lifeline with 15 minutes to play through Mathieu Valbuena, but they were unable to find a second.