The suit was filed at Haidian District court on Wednesday, World Intellectual Property Day.

"The suit is not just for my personal interest, but the whole music community, whose livelihoods depend on the protection of their intellectual property rights," Chen told Xinhua.

A pioneer of Chinese pop music, he composed the music for Zhang Yimou's Olympic video presentation, with which Beijing won the 2008 games. He was also producer of a dozen Chinese singing stars.

Chen claims he was invited to compose music for the TV series"Shen Diao Xia Lu" adapted from Jin Yong's martial arts fiction. Zhang Liangying, a singer from last year's"Super Girls", a television show similar to"American Idol", was invited to perform the theme song"Second to None". Chen made the song especially forZhang, and produced it in his own studio.

Chen agreed to give DoFala.com, a music website, exclusive broadcast and download rights. Under their agreement, DoFala was to pay Chen a fixed fee of 40,000 yuan(5,000 US dollars), and a royalty of 0.5 yuan(six U.S. cents) for each download. However, DoFala had to cancel the cooperation since the song had been found available for downloading on mop.com.

Mop.com canceled the download service after Chen made enquiries, but users could still listen to"Second to None" online. A search of mop.com shows the song has been broadcast and downloaded more than 100,000 times.

"Mop.com has obviously infringed the musician's intellectual property rights," said Dr. Wei Yanliang, a senior scholar with State Intellectual Property Office, who is acting as Chen's agent free of charge.

Huang Yunquan, DoFala.com chief executive, said the song was picked up by other websites as soon as DoFala published it."Few paid attention to our statement that the song was exclusive."

Dofala alerted other websites, Huang said."Some small websites immediately canceled the song and apologized, but a few bigger ones ignored the warning and continued to offer it for downloading."

Huang was also worried about the Web 2.0, the new Internet technology allowing users to provide content to web operators."It is designed to lower the costs of operators, but who can guarantee the content from netizens has been legally obtained?" he said.

He said the Internet needed regulation against rampant piracy, just as Chinese Internet firms were campaigning against pornographic and indecent content."We should abide by the rules for the protection of intellectual property."

The dispute has sparked controversy in chat rooms, where"Little Fish" complained the Internet was fertile ground for piracy. Users and operators should abide by the rules, and the government policing."A report mechanism on Internet piracy should also be established."

Another called"Run faster than Pig" said,"Piracy in effect helps promote the producer. It is easier for a pirated version to become popular and make money."

Wei Yanliang said the different attitudes indicated that further education on intellectual property rights was needed in China.

He said the key to protecting intellectual property was implementation of the law. China should learn from the experience of other countries, such as the United States' closure of napster.com, which had 80 million users, demanding it verify every incoming item before reopening.

Last September, baidu.com was successfully sued by a Chinese music firm for 68,000 yuan(8,500 U.S. dollars) because its MP3 search function violated the company's rights. Earlier this month, a technology company developing MP3 download software, Kuro, was sued in the first case involving P2P(peer to peer) downloading in China.

Mop.com is the largest interactive entertainment website in China. The case will open both the operations of commercial mainstream websites and behavior of Chinese Internet users to scrutiny. Enditem