Agen hooker Paula Ngauamo is set to miss seven weeks for his Top 14 club following an incident during the Rugby World Cup.
Kylan Hamdaoui scored late as Top 14 strugglers Stade Francais edged out Toulon, while Bordeaux-Begles ran riot against Clermont Auvergne.
It was another game and another win for Lyon in Top 14, where Castres were defeated by Toulouse on Saturday.
Racing 92 dominated the second half to beat Pau before La Rochelle were beaten by Toulon at Stade Mayol.
Leaders Lyon are the only unbeaten side in the Top 14 after they won a top-of-the-table encounter against Bordeaux-Begles.
Jake McIntrye amassed 22 points as Clermont Auvergne defeated Top 14 strugglers Stade Francais, as Bordeaux-Begles drew with Montpellier.
Despite seeing their try line breached for the first time this season, Lyon maintained a 100 per cent start to the season in the Top 14.
Toulon and Agen each won in the Top 14 on Sunday, with Racing 92 unable to complete a turnaround while Montpellier were outplayed.
The top two in the Top 14 claimed huge victories to stay unbeaten as both the defending champions and last year's runners-up were beaten.
Clermont Auvergne suffered a derby defeat to Top 14 new boys Brive as defending champions Toulouse earned their first win of the season.