"Les illusions de nos vingt ans" ("The illusion of our twenties") is a song by Peter, Sue and Marc sung in French that represented Switzerland at the Eurovision Song Contest 1971 in Dublin, Ireland. It was composed by Peter Reber and written by Maurice Tézé.
The song was performed 4th on the night of the contest, following Monaco's Severine with "Un banc, un arbre, une rue" and preceding Germany's Katja Ebstein with "Diese Welt". It received 78 points, placing 12th in a field of 18.
It was succeeded as Swiss representative at the 1972 contest by Veronique Mueller with "C'est la chanson de mon amour". Peter, Sue & Marc would return to represent Switzerland on three more occasions, each time singing in a different language; in 1976 with "Djambo, Djambo" in English, in 1979 with "Trödler und Co" in German and finally in 1981 with "Io senza te" in Italian, a record in Eurovision history.