The 2006 Cannes International Film Festival opened with the world premiere screening of one of the most eagerly awaited films in many years, "The Da Vinci Code".

Before the film was shown late Wednesday, the host of the opening ceremony, French actor Vincent Cassell, made an impassioned speech for a multicultural society that will be regarded in France as criticism of Interior Minister Nicolas Sarkozy's new immigration bill, which is intended to reduce the number of illegal and unskilled immigrants to France.

"This festival is for me a celebration of diversity," Cassel said.

Then the veteran American Oscar-winning actor Sidney Poitier officially opened the 59th edition of the world's most prestigious film festival.

Minutes earlier, the director of "The Da Vinci Code", Ron Howard, and its stars, Tom Hanks, Audrey Tautou and Ian McKellan climbed the red-carpeted stairway of the Palace of Festivals.

Earlier Wednesday, Howard cautioned people who are afraid they might be upset by his film not go to see it.

"There is no question the film is going to be upsetting for some people," Howard said during a press conference hours before the start of the 2006 Cannes International Film Festival.

"Don't go to see the movie if you don't want to be upset," he said.

The film has drawn sharp criticism from Christian groups around the world, who claim it blasphemes their religion and the Bible and have threatened a variety of protest actions, including boycotts.

Tom Hanks, the lead actor in the film, portraying the symbologist Robert Langdon, told journalists in Cannes that "The Da Vinci Code" was not to be taken as a reflection of reality.

"The film is a work of fiction," Hanks said. "It's part of a commercial enterprise. It's entertainment. It's not a documentary."

He also said that trying to stay true to the book was not an easy chore.

"The great advantage of the book is that Brown could explain things over five pages and more," Hanks said. "The challenge was to put that into dialogue. It required a lot of condensation."

As part of an intense 24-hour publicity campaign at Cannes for "The Da Vinci Code", the film's principals travelled to the Mediterranean resort in a specially designed high-speed Eurostar train, the Da Vinci Special, from London's Waterloo Station, a distance of 1,421 km.

The film opened in France on Wednesday and will hit screens worldwide Thursday and Friday.

In the days that follow, other film stars will march up the fabled stairway of the Palace of Festivals, with Cate Blanchett, Penelope Cruz, Justin Timberlake, Sarah Michelle Gellar, Bruce Willis, Halle Berry, Ethan Hawke, Juliette Binoche and Bob Hoskins all expected to put in an appearance.

The festival's artistic director, Thierry Fremaux, has selected 20 films from 13 nations to compete for the Palme d'Or, or Golden Palm, for best film, one of the most prestigious film awards in the world.

Favourites for the top prize include Spain's Pedro Almodovar, Aki Kaurismaki of Finland and Ken Loach of Britain.

However, a number of highly regarded members of what Fremaux called "the up-and-coming generation" of film makers - such as American Sofia Coppola, Mexico's Alejandro Gonzalez Inarritu and France's Xavier Giannoli - may spring one of the surprises the festival is famous for.

The Da Vinci Code will be screened out of competition. The awards will be announced on the last day of the festival, May 28.