Saint-Etienne have leapfrogged Rennes in the Ligue 1 table with a comfortable 2-0 victory at the Stade Geoffroy-Guichard.
The hosts took the lead in the 22nd minute when Pierre-Emerick Aubameyang took a touch to control Max Gradel's cross before firing into the far corner.
They had to wait until four minutes into the second half to extend their advantage as Renaud Cohade found the net with a fierce drive from outside of the area.
Aubameyang had a glorious chance to make it 3-0 after the hour, but the striker was denied by Rennes goalkeeper Benoit Costil after he was put through on goal.
Saint-Etienne came even closer late on when Romain Hamouma struck the crossbar before the visitors' misery was made worse by Mevlut Erding's red card for hitting Jean-Pascal Mignot in the final moments.