Dan Carter scored a late try to help Racing 92 beat Bordeaux-Bègles 22-20 and qualify for the French Top 14 playoffs.
Racing finished sixth on the log, three points ahead of Stade Français, who lost 27-26 to Montpellier.
Jake White's side finished third on the log and will therefore host a playoff qualifier against Racing. The other qualifier will see fourth-placed Toulon up against fifth-placed Castres.
La Rochelle lost their last regular season match 30-26 at Clermont, with both sides qualifying for the semi-finals, having finished first and second on the log respectively.
Round 26 results:
Brive 33 Castres 27
Clermont 30 La Rochelle 26
Grenoble 53 Lyon 21
Montpellier 27 Stade Français 26
Racing 92 22 Bordeaux-Bègles 20
Toulon 32 Pau 12
Toulouse 40 Bayonne 12
Montpellier vs Racing 92
Toulon vs Castres
La Rochelle vs TBC
Clermont vs TBC
Photo: Dave Winter/Getty Images