Iranian director Mohammad Rasoulof recalled how he had to decide within hours whether to go into exile or serve a prison sentence, saying it was still difficult to talk about it during a press conference at the Cannes Film Festival on Saturday.

Rasoulof was in the French Riviera town for the premiere of his new drama "The Seed of the Sacred Fig", almost two weeks after announcing he had fled Iran and entered into exile in the wake of his sentencing to eight years in jail and flogging.

After he learned that he had a week left before his sentence would be implemented, things moved quickly, he said, especially as authorities had caught wind of the existence of his new film.

"I had to say to myself, well, do I want to be in prison, or should I leave Iran, geographic Iran, and join the cultural Iran that exists beyond its borders?" recalled the director.

"It took me two hours to take the decision. I walked around, I paced around my house. I said goodbye to my plants that I love, and I have many, many plants in my house," he added.

Then, Rasoulof left all his belongings and walked out of the house. "It's not an easy decision to take. It still isn't easy even to talk about it today with you," he told journalists.

Iran's culture minister Mohammad Mehdi Esmaili told state media this month that Rasoulof's film had been made illegally and there would be a crackdown on movies without permits.

"The Seed of the Sacred Fig" is about a court official who grows increasingly controlling of his family during the 2022 protests over the death of Mahsa Amini, a Kurdish woman arrested by the morality police for allegedly flouting dress codes.

The film drew the longest standing ovation at the festival after its premiere on Friday night and was well received by critics who called it "mesmerizingly gripping" and "shattering".

The director, who has been arrested and detained several times for charges ranging from filming without a permit to "collusion against national security", said that the idea for the film came from years of confrontation with secret services.

"All these characters were inspired by real people, all the scenes come from real situations," he said, adding that experience has also made him adept at avoiding secret services.

"Our life is fairly similar to that of gangsters, except we are gangsters of the cinema," he joked at the news conference.