Leaders Toulon will take on fourth-placed Castres on Friday in the pick of the weekend's Top 14 action.
Despite the RBS Six Nations meaning a number of clubs will be forced to field weakened line-ups, Toulon will not have that problem. They will arrive at Stade Pierre Antoine with 12 internationals in their starting line-up, with a handful more on the bench.
Toulon, though, have not won in Castres since 1985 - and were held to a 22-22 draw there last season.
Sebastien Tillous-Borde will make his first start this year alongside Jonny Wilkinson - while Maxime Mermoz, Matt Giteau, Steffon Armitage, Bakkies Botha, Carl Hayman and Andrew Sheridan will be among the glittering array of talent on show in Toulon colours.
Castres have made five changes to the side that narrowly lost in Biarritz last time out with veteran Fijian centre Seremaia Bai and former Worcester winger Marcel Garvey among those starting.
Defending champions Toulouse host Bayonne seeking to regain some form as they enter the final quarter of the season.
Back-to-back defeats have left Toulouse 11 points off the lead and trying to cling onto the shirt-tails of Clermont, who currently hold the second automatic semi-final berth.
Clermont, though, have a tricky trip on their hands this weekend as they visit Grenoble, who have not lost on home soil since 2011.
Montpellier will be looking to keep up with the leading quartet as they host Bordeaux-Begles. Montpellier have won six games at home, where they are undefeated since mid-September, while Bordeaux are just a point off the relegation zone.
There is tight scrape in mid-table and Saturday could be a pivotal moment in the season. Perpignan host Stade Francais, while Racing Metro travel to Biarritz - with a loss for either of the hosts likely to severely dent their play-off hopes.
At the other end of the table, Agen have a golden opportunity to climb out of the relegation zone at home to bottom side Mont-de-Marsan.