Vincent Cassel as France's 'Public Enemy Number One'

CANNES — The Cannes opening weekend is crucial to a festival designed to woo the world. The focus is not so much on what's showing in the Grand Théâtre Lumière, but on the parade of stars ascending the red carpet. On Sunday, the cast of a movie-in-the-making provides the glamour, with the festival launching a tantalizing concept, the whiff of a coming attraction. For behind the scene, the first images of Thomas Langmann's two-part "Public Enemy Number One" are being shown to select professionals.

The adventures of Jacques Mesrine, the legendary bandit of the 1970s, are part of French lore, and the venture is aimed to captivate the international market. The movie is directed by Jean-François Richet. Part 1 will be released later this year; part 2 in 2009. Vincent Cassel plays Mesrine, the man of a thousand faces, as he was known. Along with Langmann, Richet, and Cassel, the other personalities who are expected on the red carpet include Gérard Depardieu, who plays Mesrine's mentor, and Cécile de France and Ludivine Sagnier, who play the women in Mesrine's life.

Cassel, who has a tall, restless body and the pale blue eyes of a changeling, has spent seven years on this project, working with Langmann: it is their baby. He has spent years researching his character and trying out different Mesrine persona.

The actor, France's favorite bad boy, is married to the actress Monica Bellucci, who represents Dior and Cartier and has been voted the Most Beautiful Woman in the World by French TV audiences. The couple have appeared together in a half dozen movies, from fantasy like "l'Appartement" (1996) and the cult "Pacte des Loups" (2001) to Gaspar Noé's pitch-black "Irréversible" (2002), which competed in Cannes.

"Monica and I team up on voice-overs, too. We're a good team, we're a lot of things." The couple have a small daughter and a small house in Paris. Bellucci lives mostly in London, where she is currently preparing to act in Rebecca Miller's "Private Lives of Pippa Lee" with Daniel Day Lewis.

Ever since his performance in Mathieu Kassovitz's "La Haine" (1995) as a tough from the Paris suburbs hit Cannes, Cassel has raced from film to film. He went from Kung Fu heroics in movies like "Dobermann" (1997), to international acts in "Ocean's Twelve" (2004) and "Derailed" (2005). In David Cronenberg's "Eastern Promises," the actor, so often type-cast as a cool athlete of gangsterism, played the crybaby son of a killer and sported a Russian accent.

And now, the curtain is being raised on his toughest job to date - a part that French actors of several generations have dreamed about. "They all wanted to play Mesrine," Cassel said. "Belmondo, Delon, Depardieu - this is a plum part because the man was a myth. But we are not making a hero of him." Indeed, Langmann and Cassel speak of the two-part film as a kind of cautionary tale, a recreation of dangerous fall-out from France's disastrous war in Algeria - not to mention the idealized post May '68 era. They feel that the name Mesrine resonates with young people today, as does Al Pacino's Scarface.

Jacques Mesrine, the restless son of middle-class parents, went off to fight in Algeria and came back to start a new life, as bank robber, killer and escape artist. He thumbed his nose at his bourgeois past, taunted his jailers, held the rich for ransom, played hide-and-seek with the press, and captivated the post-1968 generation of intellectuals with his anarchistic stance. He was also a serial collector of women. Two movies, according to Cassel and Langmann, are not too much for such a mythical character.

"Mesrine is still a popular figure because of his extraordinary sense of freedom," Cassel said. "He told everybody to go to hell. These days, we have 'Sarko' and Big Brother watching over us. Yet, we're not at portraying him as a hero, but showing his dark side. Back from the Algerian war, he started his career by killing two Arabs - I wonder what kids in the suburbs are going to say about that."

Cassel, who is used to playing unpalatable characters, trained like a champion, gaining and shedding 20 kilograms, or 44 pounds, for the part. "The hardest was gaining the weight." He donned elaborate disguises, and an array of toupees, mustaches, glasses and expressions to go with them - smiling, hearty, scowling, moody, ferocious and curiously absent.

"I had to judge the man in order to play him. He was not as lovable as the French press portrayed him, no Robin Hood - he used guns all the time. But you have to admire the risks he took.

"The fact that the genesis of the two films was so long gave me a chance to study the various drafts of the script, and I read a lot, so when we started to shoot I no longer quite knew what was in the script, but I was ready to play all kinds of scenes because I was comfortable with the guy." He was able to improvise on the set because he knew Mesrine's instincts; he had internalized the character.

Despite the long shoot, the actor said he loved every minute of it, and could go another three months, if necessary. "It's been a lot of fun. Especially when you get along with the people you work with: I never argued with anybody for eight months."

He was enthusiastic about his scenes opposite Depardieu. "He would have loved to play the part of Mesrine himself. I know that, and I felt that now I'm strong enough: I really have my own identity. Meeting him on the set I felt, 'I'm ready.' He's powerful and talented, so I wanted to see what would happen if we crossed swords - and he was great."

Jean-Pierre Cassel was set to act opposite his son, but he died just before the filming. Vincent, who looks increasingly like his father, has always remarked on the contrast between them: Cassel père was at his best playing lightweights; Cassel fils, the heavies.

He was on his own at the age of 18. "My parents were in no position to tell me what do: I grew up in various boarding schools. Then, I went to circus school to learn trapeze, high wire. I had this idea that actors should be complete. I figured that the more you learn the more creative you can be."

He moved to New York, where he lived on the Upper West Side, studying ballet and tap and acting by day, working as a bus boy at Village cafés and restaurants.

In Paris, the actor trains regularly, despite a tightly scheduled program, which has him flying to Brazil for a break between movies. He says he lost touch with Kassovitz in "an ego accident." He laughs. "I don't know exactly what happened, but he is different from the man I met years ago. I built my identity with Kassovitz, Noé and the others, I gained confidence in my craft. I didn't want to work with anybody but them.

"I don't always accept jobs; I often say no. But I like the idea of making a French movie that will travel. They don't know Mesrine in the U.S., so they will have to go for the movie without the mythology. It will be interesting."

Jacques Mesrine was killed in a police ambush in Paris. His dramatic death - some 19 bullets hit him at the wheel of his car - made one of the most spectacular covers of Paris Match, his ultimate cover story.