Saint-Etienne are still without a win in Ligue 1 this season after losing to Toulouse at Stadium Municipal.
The hosts took the lead on 35 minutes when Etienne Capoue guided Franck Tabanou's drilled corner kick into the bottom right corner.
Wissam Ben Yedder doubled Toulouse's advantage just before the hour-mark, rounding off a fast counter attack with a neat one-on-one finish from 14 yards.
Max Gradel pulled a goal back from the penalty spot in stoppage time after Romain Hamouma had been felled by Capoue, however Toulouse's victory never looked in doubt.