The decisive match late on the 22nd day of the championship and the Tarnais can still qualify for the finals.
Castres, who still has a chance to qualify for the final stage of the top 14, will move to Bayonne in a late game on Day 22 on Thursday April 29th.
The meeting was originally supposed to take place last Saturday before it was postponed in the ranks of Castres due to two positive cases of Covid-19.
The CO, 8th at kick-off, is only 2 points behind the 6th place, which is occupied by Bordeaux-Bègles.
The twelfth bayonnais want to distance themselves from the red zone.