The 24th Cannes Film Festival was held from 12 to 27 May 1971. The Palme d'Or went to The Go-Between by Joseph Losey. Wikipedia
Dates: May 12, 1971 – May 27, 1971
Location: Cannes
Awards: Palme d'Or (The Go-Between)
Closing film: Les mariés de l'an II
Opening film: Gimme Shelter