Nice strengthened their grip on the Ligue 1 standings when they beat 10-man Olympique Lyonnais 2-0 at home on Friday.
The Azurean side, who now have 23 points from nine games, lead second-placed Monaco, who lost 3-1 at Toulouse, by four points.
Nice prevailed thanks to goals by Paul Baysse and Jean-Michael Seri, who found the back of the net either side of the interval.
Lyon, who are fifth on 13 points, played more than two thirds of the game with 10 men after forward Nabil Fekir was shown a straight red card for a dangerous tackle on Baysse in the 28th minute.
Baysse opened the scoring in the fifth minute with a neat volley from inside the area.
The hosts, who started with Italian striker Mario Balotelli up front, doubled the tally with 14 minutes left when Seri fired home after Younes Belhanda's strike bounced onto the post into the way of the midfielder.
Earlier Monaco wasted a one-goal lead as Toulouse fought back following Valere Germain's fourth-minute opener. The hosts equalised through Oscar Trejo in the 65th before Martin Braithwaite struck twice in the 84th and 87th minutes.
Toulouse are third on 17 points.
On Saturday, champions Paris St Germain will move four points behind Nice if they beat Nancy.