With rapid economic growth transforming China, independent filmmaker Cui Zi'en is one of a growing number of directors dodging the censors in order to document the changes through the eyes of some of the most marginalised in Chinese society.

"We're a heroic, comic, lost generation. We have nothing," says one young man in Cui's documentary "Night Scene" about the lives of young male prostitutes in Beijing.

A film scholar and gay activist who has written nine novels including China's first gay novel, Cui has for the last 12 years focused on low-tech digital video (DV) filmmaking as his preferred means of expressing himself.

His 40-odd films have covered everything: from the only children produced by China's one-child policy imposed in the late 1970s, to the problems faced by millions of rural migrants who have flocked to the cities in search of work.

Cui, 54, began making films as soon as the technology became accessible due to falling prices in 2001.

Digital video was not only cheap but also had the added advantage of being beneath the radar of China's censors.

"The censors exert their rights over anything submitted to them," Cui told AFP in an interview in Paris.

"As I am part of the independent cinema movement, we do not recognise the authority of the censors," he said.

Instead, Cui and his fellow independent filmmakers bypass the censors and screen their work at gay or independent film festivals, in bars and at universities, post them online or distribute them on copied DVDs.

The social upheaval sparked by China's breakneck economic growth has given independent filmmakers a wealth of material.

The nation faces social problems ranging from an ageing population and the impact on future growth of the one-child policy, to graft and a gender imbalance due to the aborting of female foetuses.

Initially, Cui, an associate professor at the Film Research Institute of the Beijing Film Academy, concentrated on avant-garde features. But in 2007 he turned to documentaries.

"What I want to do in my films is to write another history of China, giving a voice to the marginalised, people whose rights are unrecognised and neglected through filming their way of life, of surviving," he said.

Two of Cui's films "Night Scene" and "Queer China, 'Comrade' China", which traces the history of homosexuality in China, are featured in a China season at Paris's Forum des Images in February.

Homosexuality remains a sensitive issue in China, where it was officially considered a form of mental illness as recently as 2001 and same-sex marriages or civil unions have no legal basis.

"Before I came out, I was someone who was well regarded and esteemed because I was a writer, film director and a teacher.

"But the moment that I came out, all this was turned on its head and I was subjected to repression," he said. Such treatment was a deterrent to others wanting to declare their sexuality, he added.

Experts in China estimate that there are between 30 and 50 million gay people in the nation of 1.3 billion, Cui said.

In addition to the difficulties of being gay in China, Cui added that he was also subjected to scrutiny by the authorities.

Government security officials once quizzed him after he attended a film festival in the US and he was later banned from collecting a literary prize awarded by a human rights organisation in New York.

Despite this, he says he is determined to carry on telling the stories of people at the bottom of Chinese society.

"The marginalised interest me, people who are fighting against life," he said.