Danish actor Mads Mikkelsen won the best actor prize for The Hunt, while the actress prize was shared between Cristina Flutur and Cosmina Stratan for Romanian movie Beyond the Hills.
British director Ken Loach collected the Jury Prize for The Angels’ Share.
The winners were revealed by the head of the jury, Italian director Nanni Moretti, on the final night of the 12-day film festival.
Haneke’s film focused on an elderly couple whose relationship is tested when the wife suffers a series of strokes.
The central roles were played by French actors Jean-Louis Trintignant and Emmanuelle Riva, who joined Haneke on stage to collect the Palme d’Or.
“This film is an illustration of the promise we made to each other, if either one of us finds ourselves in the situation that is described in the film,” said Haneke.
The Grand Prize, considered the competition’s second place, was won by Matteo Garrone’s Italian satire Reality.
Carlos Reygadas was named best director for the surrealist tale Tenebras Lux.
Head judge Moretti, who was joined on the jury by Ewan McGregor, British director Andrea Arnold and actress Diane Kruger, said none of the winners had been a unanimous verdict.