French school film is the Class act in Cannes

The Cannes Film Festival's Palme d'Or was won by the French production Entre les murs (The Class) last night. The film, directed by Laurent Cantet, used teachers and students to chronicle a year in the life of an inner-city school. "The film we wanted to make had to be a reflection of French society – multiple, many-faceted, complex," said Cantet. "Sometimes also with friction that the film does not try to cover up."

Benicio del Toro won the prize for best actor for his lead role in Guerrilla, Steven Soderbergh's biopic of Che Guevara. Accepting the award last night he dedicated it to the late revolutionary.

Many had been braced for an overtly political film to win the Palme d'Or, representing the "anti-Oscar" spirit of the festival that the firebrand jury president Sean Penn had said, a day earlier, that he was striving for.

With an eclectic choice of 22 contenders, whose gritty subjects ranged from Soderbergh's four hour, 18 minute epic to an Argentinian film set in a women's prison and an animated drama about the massacres at the Sabra and Shatila refugee camps in Lebanon, critics acknowledged that Cannes had one of its sharpest political edges for years.

Penn, who not only led the jury but appeared in the festival's closing film, What Just Happened?, had said that the winner of the Golden Palm was selected for its awareness of the "times in which we live".

He had gone further 24 hours earlier, advising his panel to "do just the opposite" of the Oscars and crown a groundbreaking, unconventional film.

"The best way to be honest is to try to emancipate ourselves from the effects of fashion, to try to find what will stay with us forever," he told Le Monde. "We've got to do the opposite of the Academy that gives out the Oscars, where manipulation and very good marketing are rewarded."

When the nominations were announced, it was evident that the shortlist was returning to its roots by selecting innovative international films.

Ari Folman's bleak, searing, animated film Waltz With Bashir had been tipped to take home the biggest prize of the festival. Several directors on this year's list, including Wim Wenders, chosen for Palermo Shooting, and Jean-Pierre and Luc Dardenne, for Le Silence de Lorna, had picked up the Palme d'Or in previous years.

The tenor of the 12-day festival – which even Penn admitted could have done with a few more comedies – had been set with opening film, Blindness, a dystopian vision of the future based on a novel by Nobel Prize-winning author Jose Saramago, with obvious political undertones.

Clint Eastwood's competition offering, Changeling, starring Angelina Jolie as a mother searching for her missing child, had been among the more serious Hollywood contenders, beside Charlie Kaufman's Synecdoche, New York.

Walter Salles and Daniela Thomas's Linha de Passe, a tale of four brothers in a Brazilian slum, had also been warmly received by critics as well as Matteo Garrone's Gomorra, a study of the criminal underworld in Naples and Nuri Bilge Ceylan's Three Monkeys, a family drama.

The Palme d'Or jury, which included the Hollywood actress Natalie Portman and Mexican director Alfonso Cuaron, was asked by Penn not to read reviews of the films which he thought might colour their judgement.The British film Hunger, directed by the artist Steve McQueen, had been recognised in the Un Certain Regard category a day earlier.