"The war never ends. Tomorrow it will start again," remarks a character in "Goodbye Julia", the first Sudanese film ever selected for Cannes.

It explores the racism fueling decades of conflict in the country, and director Mohamed Kordofani admitted to "contradictory feelings" about walking the glitzy red carpet of the Cannes Film Festival while his fellow Sudanese are cowering from bombs.

The irony is not lost on Kordofani, who did not expect his debut feature to coincide with the breakout of a new conflict in Sudan.

"Right now I am stranded in Cannes," he joked in an interview with AFP on a seaside terrace overlooking a flotilla of yachts, before adding on a serious note that he was "heartbroken" by the conflict and the fact he could not go home.

"The bombing needs to stop," said the former aircraft engineer, who packed in his career to start a film production company.

"Goodbye Julia" is playing in the Un Certain Regard category in Cannes, a segment focusing on young, innovative talent.

The film starts in 2005 after the end of an earlier bout of fighting, between Khartoum and the separatist south, and ends as South Sudan gains independence in 2011.

It tells the story of how a covered-up murder brings a southern Sudanese woman, Julia, into contact with a northern Sudanese woman, Mona, and her overbearing conservative husband.

'My own transformation'

The two women's friendship is complex, and the racist undercurrent between Arabs and black Africans that stalks the Middle East and North Africa is on stark display.

Mona's husband refers to the Southerners as "slaves" and "savages", and she is forced to confront her own ingrained racism, while gender roles are also explored.

Kordofani said he was inspired by how his own views had changed over the past decade.

"I started to review how I was behaving in my previous relationships. I reviewed my own racism."