Laussucq said: "This was a great result for us and it is going to be a special moment for us to play in another European final.
"We know it will be tough, whoever we play in the final, but we will go to Dublin determined to become the first Stade team to win a European title."
Jerome Porical scored 20 points after David Lyons had claimed the other try as Stade recovered from conceding two first-half tries.
Laussucq said: "We knew what a big challenge it would be to play Perpignan in their home stadium but our defence was strong and we took our chances to score when they came.
"It was not a beautiful game but we showed how much we wanted to win.
"Perhaps we were lucky only to be four points behind at half-time but we were strong in the second half and played very smart rugby in the last ten minutes."
James Hook looked to have guided Perpignan to their first European final since 1999 but Porical kicked two late penalties, including the winner that deflected off both the post and crossbar.
Laussucq said: "I'm very happy for him [Porical]. This was a big game for him to come back to Perpignan but it could not have gone better. He scored a wonderful try, kicked the winning points and was man of the match even with the crowd whistling at him."