Little-known film festival fact: Cannes is the last refuge of a mime. The children of Marcel Marceau may have been hooted out of every other public venue, but they can be seen cluttering the Croisette with their fey antics. There's the slouching fellow dipped in black paint; the gold-plated one in the garb and attitude of heroic statuary; the clown who stands inert until small children pass by, then with an abrupt movement frightens them to bits. So it was appropriate that the 49th Festival International du Film should, in a mimelike gesture of poetic banality, give its most popular prize to a film by Belgian director Jaco van Dormael, a former mime.

As expected, the Cannes jury headed by Francis Coppola gave its top awards to films set in the British Isles. Mike Leigh's blithe, London-based family drama Secrets and Lies won the Palme d'Or, with Leigh's leading lady, Brenda Blethyn, earning the nod for Best Actress; and Lars von Trier's hyperemotional Scottish fable, Breaking the Waves, took the runner-up Grand Jury Prize. Polite applause greeted the awards for direction (Joel Coen, Fargo) and screenplay (Jacques Audiard, Un heros tres discret [A Self-Made Hero]), while a scattering of boos attended a prize for "audacity and innovation" given to David Cronenberg's Crash, that grim, sleek melange of twisted metal and twisted minds. But the fancy-dress crowd at the closing-night ceremonies rose to its feet only once: when Coppola announced that the citation for Best Actor would be shared by Daniel Auteuil and Pascal Duquenne, the stars of Van Dormael's Le Huitieme Jour (The Eighth Day).

Duquenne, who plays a young man with Down syndrome befriended by Auteuil's harried business executive, is in fact afflicted with the condition the film calls mongolism. His triumph brought tears to the audience in Cannes' Grand Palais and watching the Palmares on TV in Europe and abroad. Auteuil then cued a saving spurt of laughter as he pointed to the two comely presenters of the award, Hollywood's sister-actresses Rosanna and Patricia Arquette, and impishly told Duquenne, "These are our fiances for the evening."

That may not have been the case, but Europe was certainly Duquenne's for the rest of the week. His thick, infectious smile blanketed the front pages of French newspapers the day after the ceremony, and the country's top TV network, TeleFrance 1, led its eight o'clock news with a long report on Duquenne's victory and its implications for those with Down syndrome. The Eighth Day was no longer merely a movie. It had become what every journalist loves to discover or invent--an issue--even as it blossomed into every press agent's dream: an international hit.

Which is just as well, since as a mere movie The Eighth Day is pretty darned mere. It borrows from prizewinning Hollywood films about the slow witted--Of Mice and Men, Charly, Rain Man--as it takes an ordinary man and a disadvantaged but extraordinary one on the road to exchange lessons of friendship and hardship. Harry (Auteuil) is a successful businessman at a crisis point; Georges (Duquenne) has run away from the institution that is his home. The two men meet, with a thud, on a Belgian highway, and after some rough patches they become buddies, road warriors, the closest and warmest of.

Oh, why bother tracing the rest of the plot? You could chart it in your sleep, and do a better job than Van Dormael. Virtually every dramatic conflict occurs because Harry, who tries to keep an eye on Georges at every moment, has just stepped out of his friend's sight when Georges gets into some scrape over buying shoes or chocolates--or a van that Georges and his pals from the institution hijack and drive brazenly through a mall. Such fun! The world is mad, and only these handicapped children of God are close enough to him to know how precious love and life are.

It would be lovely if such romantic notions were true, and if good intentions automatically led to good films. Van Dormael has already made one of those: the 1991 Toto le heros, a densely beautiful memory movie in which Duquenne had a small role as the protagonist's brother. The Eighth Day begins where Toto left off, in rich, surreal imagery depicting God's creation of the world as Georges sees it. It's an amazing five minutes or so of cinema; then the film's title flashes on the screen and everything immediately turns cloyingly manipulative. Rarely has a film gone from great to gruesome in so brief a span.

Van Dormael's one coup was to cast Duquenne as Georges. No Dustin Hoffman or Tom Hanks doing a dynamite acting job; this is the real thing, a documentary record of a handicapped man playing someone like himself. Though the gambit is not original (Christopher Burke, who has Down syndrome, played a similar character in the U.S. TV drama Life Goes On from 1989 to 1993), it paid off in Cannes and beyond. Duquenne is indeed a resourceful actor with loads of burly charm, but he is sabotaged by the mean uses to which Van Dormael puts him, in a movie that degenerates from poignant drama to carnival exhibition. The Cannes Jury had it half right. To Duquenne, a brisk bravo! To Van Dormael: For shame.