Saint-Etienne went top of the French first division on Friday when substitute Romain Hamouma grabbed a second-half goal to secure a 1-0 win over Valenciennes.
But their lead could be short-lived.
They have 25 points, the same as previous leaders Lyon, but have played two games more and lead the way on goal difference.
Lyon, who face Toulouse on Sunday, will face Saint-Etienne in two weeks’ time.
Hamouma came on as a 63rd-minute substitute for Ivory Coast star Max-Alain Gradel and found the target 10 minutes later with the only goal of the game which stretched his team’s undefeated run to nine games.
Hamouma scored with a right-foot drive after a fine pass from Renaud Cohade.
St Etienne go top in France
