The French-language feature "Amour" follows an elderly married couple, former music teachers, who are enjoying a comfortable retirement in Paris before Anne, played by Emmanuelle Riva, suffers a stroke.

"It's a very powerful film and it's a very sober film. It might almost resemble a documentary on this terrible and very painful event," Riva, best known for 1959's "Hiroshima Mon Amour", told a news conference.

"It's tremendously simple and because it's so simple it's so powerful," she added, speaking in French.

Tears flowed at the press screening ahead of the film's red carpet world premiere on Sunday, and judging by critics' enthusiastic tweets and blogs immediately afterwards, Haneke is the early frontrunner for the festival's top prize, the Palme d'Or.

Anne's loving husband Georges, played by Jean-Louis Trintignant, admirably struggles to adapt as Anne's situation deteriorates, but Haneke is unsparing in showing us the banality and sadness of a daily routine that defines their new life.

We see Georges helping Anne get out of the bed into her wheelchair, go to the bathroom, or with monotonous physical therapy, and with each, the viewer is sucked into their world, painfully aware that death is approaching.

"None of that deserves to be shown," Georges tells his daughter Eva, played by Isabelle Huppert, as Anne's speech deteriorates into incoherent mumbling.

OUT OF RETIREMENT

Haneke convinced veteran actor Trintignant, 81, to come out of retirement for the role of Georges. Trintignant won the best actor award at Cannes in 1969 for political thriller "Z".

"I suffered greatly but ... I'm very pleased by our work," Trintignant said. "It was painful but very beautiful at the same time."

Haneke, winner of the Palme d'Or for "The White Ribbon" in 2009 and a Cannes regular, said his new film is not a commentary on the elderly, or society's treatment of them.

Rather, he said, he was proud to make a "simple" film about a relationship and its inevitable end.

"I never write a film to show something," Haneke said, speaking in French.

"Once you reach a given age of necessity you have to contend with the suffering of someone you love ... it's inevitable. That's what gave rise to this project, I was not trying to say anything about society per se."

The director is known for being demanding on his actors. But a pigeon with a cameo appearance was also on the receiving end of Haneke's orders.

"So long as he didn't get what he really wanted, he (Haneke) made the pigeon do things again and again," Trintignant said. "In fact there were two pigeons, because one of them gave up."

"He didn't think the pigeon was very good."

(This story is corrected in graf 13 to show Haneke spoke in French)

(Reporting By Alexandria Sage; Editing by Maria Golovnina)

• A Permanent Economic Emergency