Anthony Tuitavake was sent off as Racing 92 lost 23-19 at Agen in the Top 14.
Tuitavake was shown a straight red card for a dump takle on Julien Heriteau late in the first half. At that stage Racing were 7-3 ahead thanks to a try from Brice Dulin.
However, they found themselves behind at the break thanks to a converted score from Ricky Januarie, and Agen stretched their lead with a George Tinsley try.
Racing hit back with tries from Teddy Thomas and Bernard Le Roux but were unable to reel in their hosts, who had built a nine-point lead with seven minutes left thanks to the boot of Jake McIntyre.
Elsewhere, Stade Francais ran in five tries as they recorded a convincing win over La Rochelle at Stade Jean Bouin.
Stade were 30-7 in front at half time thanks to tries from Anoine Burban, Alexandre Flanquart, Sergio Parisse and Tony Ensor, two of which were converted by Jules Plisson who also added a pair of penalties.
Marvin O’Connor grabbed Stade’s fourth try before La Rochell — who had scored in the first half through Dany Priso — hit back through Afaesetiti Amosa and a penalty try. Ryan Lamb added a second-half penalty and conversion but it was never going to be enough to stop Stade.
Montpellier, meanwhile, continued their impressive start to the season with a five-try 37-6 win over Oyonnax.
Bismarck du Plessis, Ruan Pienaar, Francois Steyn, Henry Immelmen and Louis Picamoles touched down for the hosts. Pienaar also added 12 points with his boot.
Oyannax’s only response came via two Christopher Ruiz penalties.
Castres also scored five tries as they won an entertaining clash with Bordeaux Begles 33-19.
Bordeaux took the lead through Yann Lesgourgues’ 11th-minute try but Castres hit back as Loic Jacquet, Maama Vaipulu, David Smith, Alex Tulou and Rory Kockott scored unanswered.
Lyon made it two wins from two as Baptiste Couilloud and Alexis Palisson scored second-half tries to secure a 29-14 win over Brive.
And in Saturday’s late game, Toulouse secured a 23-19 win over Pau thanks to tries from Maxime Medard and Cheslin Kolbe.