Late goals by strikers Sammy Traore and Mamadou Bagayoko gave mid-table Nice a surprise 2-1 triumph at Ligue 1 leaders Paris St Germain on Saturday.
French league leaders Olympique Lyon drew 0-0 at Paris St Germain in a bad-tempered league match on Friday as the Parisians played for more than an hour with 10 men.
Struggling Paris St Germain say they should not be written off yet despite failing to win a match this season.
Monaco moved top of Ligue 1 after a late winner by striker Emmanuel Adebayor on Sunday sealed troubled Paris St Germain's second consecutive home defeat.
Olympique Marseille host Ligue 1 leaders Toulouse on Saturday (1900 BST) knowing they must improve on the recent performances which have left them 10th in the table.
After two seasons of Lyon championships, Pierre Serisier says Marseille and PSG will be eager to challenge for Ligue 1.
Brazilian World Cup winner Ronaldinho will remain at Paris St Germain next season after scoring twice to help them reach the French Cup final, the club's major shareholder pledged on Monday.