The world's biggest film festival opened in Cannes Wednesday with a blast of controversy as critics mercilessly savaged the opening movie about Hollywood-darling-turned-princess Grace of Monaco. The movie's star Nicole Kidman, Sofia Coppola, Willem Dafoe, Audrey Tautou and jury head Jane Campion were among the film world luminaries who walked up the 24 steps of the festival hall in the French Riviera resort, under the cool gaze of the late Italian heartthrob Marcello Mastroianni whose giant portrait adorned the facade. Ryan Gosling, David Cronenberg and Sophia Loren are also set to make an appearance later in the 67th Cannes Film Festival, where directorial big guns will go head-to-head in a year of comebacks, swansongs and star debuts. But for film-makers behind the opening movie, the festivities were bittersweet as the Monaco princely family furiously disavowed a film they say bears no resemblance to reality and critics who got a sneak preview made no secret of their contempt. "The cringe-factor is ionospherically high," The Guardian film maestro Peter Bradshaw wrote. "A fleet of ambulances may have to be stationed outside the Palais to take tuxed audiences to hospital afterwards to have their toes uncurled under general anaesthetic." On the red carpet, Kidman sparkled in a blue, jewelled strapless dress, smiling for the cameras next to downcast-looking French director Olivier Dahan. In the film, the Australian-born actress portrays an unhappy Grace who sleeps in a separate bedroom to Prince Rainier, even contemplating divorce before rising to the challenge of being a princess and helping her lost husband solve a 1962 political crisis with France. - Princely frown, transatlantic row - Grace's children Prince Albert II and his sisters Caroline and Stephanie have publicly rejected a film they say "has been misappropriated for purely commercial purposes". "This film should never have existed," Stephanie of Monaco told local daily Nice Matin. Describing the controversy as "awkward" in a press conference earlier on Wednesday, Kidman sought to reassure the family that the film bore no "malice" towards them or towards Grace and Prince Rainier, played by a chain-smoking Tim Roth. "It's fictionalised, it's not a biopic," she said, echoing what Dahan has previously said. The French director had been locked in a long-standing tussle with US distributor Harvey Weinstein over the final version of the film. Weinstein had reportedly considered dropping the rights to the film altogether, but Dahan said Wednesday an agreement had been reached under which the movie mogul will distribute the French director's version in the United States. "There is no dispute anymore, everything has been resolved. We're working together, and I'm happy about it," Dahan told reporters. According to entertainment industry magazine Variety, Weinstein will acquire the rights for considerably less money than he had originally planned to pay. - Cheeky dance with Kidman - The opening ceremony in the festival hall's biggest movie theatre saw the man behind the spellbinding soundtrack to Campion's 1993 Palme d'Or winner "The Piano" -- Michael Nyman -- take to the piano to welcome the jury president on stage. Master of ceremonies Lambert Wilson, a prolific French actor, also had a cheeky dance with Kidman to much applause. Chiara Mastroianni and "Gravity" director Alfonso Cuaron then formally opened the May 14-25 extravaganza, during which 18 films will compete for the top Palme d'Or prize. The festival will see Canadian heartthrob Gosling present his directorial debut "Lost River", and films by 25-year-old whizz kid Xavier Dolan, veteran director Jean-Luc Godard and "Men in Black" actor Tommy Lee Jones will also compete. And while two of the films running for the Palme d'Or are by women -- Japan's Naomi Kawase ("Still the Water") and Italy's Alice Rohrwacher ("The Wonders") -- Campion bemoaned the industry's bias against women. "I think you would have to say that there's some inherent sexism in the industry," she told reporters. "It does feel very undemocratic and women do notice. Time and time again we don't get our share of representation," she said, adding that men seemed to "eat all the cake." On the sidelines of the competitions, muscle men Sylvester Stallone, Harrison Ford and Arnold Schwarzenegger will take a trip to the resort on board a tank to promote their film "The Expendables 3". Abel Ferrara's racy "Welcome to New York" in which Gerard Depardieu plays a character much like the disgraced former head of the IMF Dominique Strauss-Kahn will also get a private industry preview during the festival. And to round off this year's festivities, US Cannes-lover Quentin Tarantino will showcase "A Fistful of Dollars" at the closing ceremony, in a glitzy celebration of the 50th anniversary of spaghetti westerns.