The highly anticipated biopic is about the Hollywood star’s marriage to the tax haven’s ruler, Prince Rainier III.
The film also stars Tim Roth as Rainier and UK actors Robert Lindsay as Greek shipping billionaire Aristotle Onassis, and Derek Jacobi as Count Fernando D’Aillieres.
But Grace Kelly’s children, Prince Albert and sisters, Princess Caroline and Princess Stephanie, aren’t fans of the movie and neither are most critics.
The royal family, initially on board with the film, unleashed an attack in January, calling several scenes “pure fiction.”
They also called the picture “pointlessly glamorized and historically inaccurate,” according to French daily le Figaro.
Film critics, mostly European, have also poo-poo’d the picture.
“It’s an easy watch, lush, stylish… and is often side-splittingly funny,” critic Phil de Semlyen wrote in Empire. “The trouble is, it’s not actually meant to be a comedy.”
The Hollywood Reporter also trashed the film, unusual for the usually gushing trade publication. Critic Stephen Dalton called the movie “a stiff, stagey, thuddingly earnest affair which has generated far more drama off screen than on.”
Kelly married Rainier in 1956 and the film focuses on a particularly tense period in their marriage in 1961. Rainier was under pressure diplomatically from France, and Director Alfred Hitchcock was trying to lure Kelly back to Hollywood to star in a film.
Kelly died at age 52 in 1982 in a car accident on a treacherous Monaco road.
The movie is due for release in 2014. Follow TheImproper on Twitter for the latest updates from Cannes.