Perpignan, Stade Franšais, Wasps and Connacht are in contention to feature in next season's Heineken Cup, depending on who claims the Challenge Cup.
With a French team guaranteed to claim the Heineken Cup crown on May 18, next season's edition of Europe's elite competition will feature an additional side from the Top 14.
The Heineken Cup winners are automatically qualified to the defend their title the following season and since finalists Clermont and Toulon have already secured a European berth via a top-six finish in the French championship, an additional French club will make the cut.
That team will be either Stade Franšais or Perpignan.
Perpignan have already secured seventh place in the Top 14 but they could lose out if their rivals from Paris claim the Challenge Cup title, which also carries with it a berth in the top flight.
Stade Franšais - who narrowly beat Perpignan in Friday's semi-final - meet Leinster in the Challenge Cup Final in Dublin on May 17.
If Stade Franšais win the Challenge Cup, London Wasps will also qualify for next season's Heineken Cup as the 24th team via their European Ranking.
A victory for Leinster, who are also already qualified, will secure a fourth ticket into the Heineken Cup for countrymen Connacht for the third season in a row along with Perpignan.
If Stade Franšais qualify, they will feature in Europe's top flight for the first time since 2010. If Perpignan make the cut, it'll be their first participation since 2011, when they made the semi-finals.
Wasps are two-time European champions 2004 and 2007 but have not played in the tournament since 2011, when they failed to progress past the pool stages.
This year's Heineken Cup Final will be the fourth all-French decider. Toulouse won the previous three - against Perpignan in 2003, Stade Franšais in 2005 and Biarritz in 2010.