"No One Knows About Persian Cats" is co-scripted by Roxana Saberi, the U.S.-Iranian journalist released from jail Monday after serving four months of an eight-year sentence for allegedly spying for the United States.
The story centers on two musicians who form a clandestine music group after being released from prison.
Saberi shares screenwriting credits with Hossein M. Abkenar and the film's director, Bahman Ghobadi.
Ghobadi announced last month that he is Saberi's Fiancé and had appealed to the Iranian authorities for her release.
Her family did not confirm the pair were engaged, but said they were close friends.
Ghobadi was expected to travel to Cannes for the movie's screening Thursday in the festival's Un Certain Regard sidebar. Saberi was not expected to be with him.
A docudrama about Iran's underground music scene, "Persian Cats" was filmed covertly in Tehran without permission from Iranian authorities.
In an interview included in the film's production notes, Ghobadi said that before he made the film, "I was sad and disheartened because my last film had been censored and because I couldn't obtain permission for my next project."
He said Saberi had encouraged him "to make a film about the situation in which I found myself."
Ghobadi, an Iranian filmmaker of Kurdish origin, has won several prizes at European and Asian festivals for his films, which include 2000's "A Time for Drunken Horses" and 2005's "Half Moon."
His movies, which often deal with the experiences of Iranian Kurds living in the border regions with Iraq, have faced censorship in Iran.
By Jill Lawless