PARIS: A controversial biographical film on Princess Grace of Monaco, which has been slammed by the former Hollywood star's children as “pure fiction”, will open the Cannes film festival, the organisers said on Friday.

The world preview of “Grace of Monaco” will take place on May 14 in the out of competition category, a statement said.

It will simultaneously be released in France and several cities around the world.

The 67th Cannes film festival will run from May 14-25 in the southern France resort town.

The film, directed by France's Olivier Dahan and featuring Australian actress Nicole Kidman as Grace Kelly, the Hollywood star-turned-princess, and British actor Tim Roth as her husband Prince Rainier, has been mired in controversy.

Dahan is locked in a months-long standoff with the film's US producer Harvey Weinstein. According to the Hollywood Reporter there is no release date for the movie in the United States.

Dahan had told French newspaper Liberation that he was being “blackmailed”by Weinstein into signing off on a new edit which did not represent his original vision.

“There are two versions of the film, mine and his, which I find catastrophic,” he had said, adding: “They want a commercial film smelling of daisies.”

The film revolves around the fairytale couple, whose 1956 nuptials were labelled “the marriage of the century” in the popular press. It tracks events at a time when France was threatening to annex the tiny principality on its southern coast.

The couple's children, Prince Albert and the Princesses Caroline and Stephanie, have said the film was “pure fiction.”

”It tells a story, rewritten and unnecessarily glamorised... containing significant historical inaccuracies and a series of purely fictional scenes,” the royals said in a statement.

The statement said the royal family had been granted access to the script and requested several changes, but the requests were not taken into account.

The biopic focuses on a six-month period in 1962 when Monaco was in a heated tax dispute with France and Alfred Hitchcock offered Kelly a chance to return to acting in a new film he was planning called 'Marnie'. Princess Grace ultimately did not do the film.