Fickou starts alongside Mathieu Bastareaud in the centres against Ireland, who know a win will likely secure them the RBS 6 Nations title.
Saint-Andre has made three other changes with Remi Tales starting at fly-half in place of Jules Plisson, while Dimitri Szarzewski comes back as hooker in place of Brice Mach and Louis Picamoles returns to the back-row.
But it is Fickou's inclusion that has most excited Saint-Andre, who is keen to see what the teenager can do from the start.
"He is in form, he is fast," said Saint-Andre. "We need to see his talent on show from the start.
"Picamoles will alternate with Damien Chouly during the game.
"But I don't want to say any more regarding our strategy, as I'm sure there are Irish journalists in the room."