Saints will face Connacht in a Champions Cup play-off at Franklin's Gardens next Saturday after Stade Francais beat Gloucester in the Challenge Cup final.
Had Gloucester won, they would have headed into the Champions Cup play-offs and hosted Connacht at Kingsholm.
But they were beaten 25-17 in Edinburgh on Friday night, with Stade recovering from 10-0 down to claim Challenge Cup glory.
That means Saints, who finished seventh in the Aviva Premiership, will now be the ones taking the play-off spot, with their game against the Irish side taking place at 4pm at the
If Jim Mallinder's men can beat Connacht, they will host the winner of the other play-off, between Stade Francais and Cardiff Blues in Paris, at the Gardens on Friday, May 26 (kick-off 7.45pm).
Details of tickets for the Connacht clash can be found on the Saints website: www.northamptonsaints.co.uk/news/latest-headlines/2017/may-2017/play-off-tickets-on-sale-now/
Champions Cup play-offs...
Friday, May 19: Play-off 2: Stade Français Paris v Cardiff Blues, Stade Jean Bouin
Saturday, May 20: Play-off 1: Saints v Connacht Rugby, Franklin's Gardens 4pm
Play-off final: Friday 26 May: Winner play-off 1 v winner play-off 2 (19.45)
The winner of Play-off 1 will have home advantage