PSG extended their lead to 13 points at the top of Ligue 1 after winning 2-1 away at Lorient on Saturday.
Gazelec Ajaccio recorded their first-ever Ligue 1 victory on Saturday, while Montpellier beat Bastia to move out of the bottom three.
Hatem Ben Arfa scored twice, including a superb solo effort, as 10-man Nice ended St Etienne's five-match winning run.
Fabinho scored a controversial penalty in the fifth minute of stoppage time as Monaco came from 2-0 down to win 3-2 at Ligue 1 basement boys Montpellier.
Paris St Germain preserved their unbeaten start to the season thanks to Edinson Cavani's late equaliser at Reims.
Montpellier climbed off the bottom of Ligue 1 but have still not scored a goal following a 0-0 draw at Troyes, while Reims went top with a 4-1 win over Lorient.