Director Amat Escalante (C) poses with cast members Armando Espitia (R) and Andrea Vergara during a photocall for the film 'Heli' during the 66th Cannes Film Festival in Cannes May 16, 2013

A man stripped to his underwear, his mouth covered with duct tape, hangs from an overpass - the brutal opening scenes of the movie kick-starting the main competition for the Cannes film festival.

True to the variety on offer at the influential jamboree, the second picture on Thursday began with a shot of a nubile young woman sunbathing topless on a beach, watched by a voyeur.

"Heli" by Mexican director Amat Escalante and "Jeune & Jolie" by France's Francois Ozon were the first two of 20 films competing for the event's coveted Palme D'Or award.

Director and jury member Ang Lee praised the diversity on offer at the 12-day event on the French Riviera.

"There are different political, social issues, different styles, (the) different charm and charisma of certain filmmakers," said Lee, who won the 2013 Oscar for Best Director with his "Life of Pi".

"I hope that there is something that just wows us. Something that we cannot even verbalize and we'll all look at each other: 'Oh my God, that's a Palme d'Or!' I hope that happens," he told reporters on Wednesday night.