Stade Francais will face Northampton Saints or Connacht in the European Champions Cup play-off final after coming from behind to beat Cardiff Blues 46-21 in Paris on Friday.
Stade, who could only finish seventh in the Top 14 but won last week's Challenge Cup final against Gloucester at Murrayfield, opened the scoring through Morne Steyn's early penalty, but it was the Blues who led going into the half-time break.
Willis Halaholo started the move for the opening try by breaking out of defence, and from a subsequent line-out, Gareth Anscombe set up Macauley Cook to cross in the 20th minute, before Anscombe added the extras.
Just three minutes later, Stade halted Halaholo and Lloyd Williams just before the line, but could not prevent Nick Williams from barging over, followed by another Anscombe conversion.
The hosts returned fire thanks to captain Sergio Parisse, who attacked from space to create a try for Waisea Vuidravuwalu, Steyn converting the wing's score.
The captain, together with fellow back-rower Antoine Burban and left-wing Sekou Macalou were involved again as substitute prop Giorgi Melikidze crossed two minutes into the second half, Steyn converting to put Stade in front.
Meyer Bosman then put in Mathieu De Giovanni and that proved the trigger for the home team to run away with it, Macalou touching down twice in the space of five minutes late in the second half.
Cook did pull one back with his second of the night, but Laurent Panis and Clement Daguin made certain of the victory with tries in the last 10 minutes, influential skipper Parisse involved in the build-up to both.
Saints hosts Connacht at Franklin's Gardens on Saturday, with a spot in the decider against Stade next Friday up for grabs. The winner of the final will claim the last remaining spot in next season's Champions Cup.