Eight hours after our meeting, it's Cantet to whom Robert De Niro presents the Palme d'Or. The director is followed onto the stage by his army of teenage actors who play students in his film about a year in the life of a high school in Paris' 20th arrondissement. It seems an apt way to commemorate the 40th anniversary of the mid-festival shutdown in 1968 by filmmakers eager to show support for student activists in Paris.

The spectre of May 1968 haunted the festival for months, with many expecting the event to be heavily politicised.

The decision of the festival's general delegate, Thierry Fremaux, to present some of the films that failed to make it to the event's screens because of the disruption 40 years ago heightened expectations of a rekindling of the political spirit of 1968, as did the appointment of outspoken actor Sean Penn as president of the jury.

The composition of the nine-strong panel added to the speculation. Its members included Bouchareb (the French filmmaker behind Days of Glory, credited with leading to changes in the treatment of Maghrebi veterans who fought for France during the second world war), Marjane Satrapi (director of last year's animated feature Persepolis) and Apichatpong Weerasethakul (a Thai director known for battling his country's draconian censors).

But it hasn't been a year for explicit political films such as Michael Moore's Fahrenheit 9/11 or Ken Loach's The Wind that Shakes the Barley, Palme d'Or winners in 2004 and 2006 respectively.

This year's selection hasn't been socially disengaged, but critical in more subtle ways. The Class, for instance, is a gripping docu-drama pitting a young and hardly saintly schoolteacher (played by Francois Begaudeau) against his rowdy, snarky and sometimes openly hostile charges, with plenty of food for thought about the essence of education, with class and cultural schisms thrown in for good measure.

Folman's Waltz with Bashir is probably the most politically-charged film of the festival, but its anti-war message is conveyed much better - both artistically and ideologically - than by its Iraq-war American counterparts, Redacted and In the Valley of Elah.

Paolo Sorrentino's Il Divo tackles the shady dealings of former Italian premier Giulio Andreotti in an almost comical way. Steven Soderbergh's Che, a sprawling, obviously unfinished four-hour film about Che Guevara, is also a more a character study of the revolutionary rather than a political diatribe heaping praise upon the man's political ideals.

Other issues in the limelight in this year's competition have included the problems of post-industrial societies (Jia Zhangke's 24 City), the debate about women prisoners nurturing their babies in detention (Pablo Trapero's Leonera) and identity politics in the internet age (Atom Egoyan's Adoration). Some stories are allegories of modern illnesses, such as Fernando Meirelles' adaptation of Jose Saramago's Blindness (about the collapse of social order as the entire human race loses its eyesight), or Lucretia Martel's The Headless Woman (the story of how a hit-and-run driver's trauma is ignored, or normalised, by her family and friends and a metaphor for how recent chapters in Argentinian history are being swept under the carpet).

Fremaux's festival ethos is perhaps embodied in Steve McQueen's Hunger, which opened the Un Certain Regard side event and won the Camera d'Or, the prize for first-time filmmakers. Revolving around hunger strikes by former IRA members at Maze prison in 1981, the film is hardly a successor to The Wind that Shakes the Barley, but McQueen, a Turner Prize-winning artist, delivers a work that thrives more as an artistic experiment and an exploration of extreme behaviour than a realist re-enactment of one of the most tragic periods in the Troubles.

The programme has allayed fears of a loss of direction and artistic merit at the world's biggest film festival, a paradoxical beast that doubles as both an orgy of showbiz glamour and a showcase for international art house cinema.

The uncertainties that dogged the festival before it began - rumours about a shortage of good films to select from as the announcement of its lineup was delayed for a week, for instance - have been proved wrong, even though this year's edition could be summed up as solid rather than spectacular (and brought down by a few duds, such as Wim Wenders' embarrassingly shapeless Palermo Shooting, with Dennis Hopper playing an arrow-shooting but tender-hearted version of the Grim Reaper, and Philippe Garrel's self-indulgent romance Frontiers of Dawn).

Unlike the Berlin Film Festival, which has in recent years opted for headline-grabbing but artistically underwhelming fare such as this year's Golden Bear winner Elite Squad, Cannes has again managed an equilibrium that accommodates Hollywood product (the new Indiana Jones film and Kung Fu Panda were out-of-competition entries this year) alongside the work of auteurs (such as Nuri Bilge Ceylan and Kornel Mundruczo) and also new cinema (Singaporean director Eric Khoo's moving father-son drama My Magic and Brillante Mendoza's technically uneven Serbis, a hard-core probe into life at a porn cinema).

But if the festival is to undergo a renewal of artistic direction as it enters its sixth decade - with an increasing emphasis on young talent rather established practitioners - it won't happen overnight.

As wags on the Croisette say, festivals after big anniversaries are always in the shadow of the celebrations of the previous year, and this year's has lacked hard-hitting surprises. There was no clear-cut winner (last year the near-perfect Romanian abortion drama 4 Months, 3 Weeks and 2 Days was a shoo-in) until Cantet's film, and it's been a slow year all round, both at the festival and also at the Marche de Film, the marketplace that runs in parallel with the main event.

But it would be premature to pronounce a downturn in the fortunes of the festival and its mix of new talent, old hands and occasional bellyflops from big-name filmmakers.

It's always a heartening experience that offers plenty to talk about - and pleasant surprises too, as Cantet's film shows.