Paris (AFP) - Castres and Montpellier qualified directly for the Top 14 semi-finals on Sunday with defending champions Toulouse and newly-crowned European champions La Rochelle going into the play-offs.
Toulouse and La Rochelle set up a revenge clash of last season's final with a place in the semi-finals in Nice on June 17-18 at stake just like third placed Bordeaux-Bègles and Racing 92 in sixth.
Racing 92 had to fight to reach the final stages for the 12th consecutive time since the 2009-2010 season, with a 21-16 win over Toulon who paid for indiscipline.
As a result, Toulon finish eighth to miss out on the play-offs.
Toulouse crushed relegated Biarritz 80-7 with a 12-try blitz while La Rochelle edged Lyon 29-26.
Castres confirmed their good form against Pau 26-16 to finish top of the standings, ahead of Montpellier, who lost 20-15 at Clermont but took advantage of Bordeaux-Begles' 22-15 defeat at Perpignan, to qualify directly for the semi-finals.
Clermont, seventh, and Lyon, winner of the European Challenge this season, will compete with the six teams qualified for the final phase in the next edition of the Champions Cup, where South African franchises will feature for the first time.
Meanwhile Perpignan, in 13th, will play for their Top 14 survival against Pro D2 finalist Mont-de-Marsan.
Earlier Bayonne cemented their return to the Top 14 a year after their painful relegation following a dominant 49-20 win at Mont-de-Marsan.
Bayonne's six tries crushed their rivals who were hit by the sin binning of South African fly-half Willie Du Plessis after 54 minutes.