A Chinese scholar has filed a lawsuit against the service provider Sina Weibo, China's largest microblog platform, after it shut down his Weibo account for the second time in September without explanation.

Zhang Yaojie, a well-known scholar and biographer, filed his suit with the People's Court in Haidian district in Beijing, on January 8, asking the provider to restore his Weibo account and refund the membership fee that was paid while his account was closed.

Zhang registered a free Sina Weibo account in February last year and became a Weibo VIP member in August paying a monthly fee of 10 yuan ($1.61) to access additional services.

Zhang told the Global Times that his postings contained no sensitive content and he cannot understand why his account was closed. His Tencent microblog, which has not been closed, includes many threads containing comments about the current political system.

Zhang filed complaints with Weibo but only received formatted replies saying his complaints had been received and customer service staff would contact him by e-mail.

"I understand that the service provider sometimes has to delete some posts and so I try to only repost other people's entries, but they still shut down my account without any explanation or notification," Zhang said.

Sina Weibo is continuing to collect Zhang's 10-yuan monthly membership fee.

"The provider has breached its contract with Zhang and violated his freedom of expression," Wang Zhenyu, Zhang's lawyer, told the Global Times.

Wang said Sina is aware of the lawsuit even though the court has not yet accepted the case. He thinks the court might attempt mediation before filing the case and they are waiting for a reply from Sina.

"Sina needs time to communicate between its departments and we will give them the time to do that," Wang said.

"The service provider should abide Chinese laws. I want to give Sina and more importantly the authorities a warning that they should not deny people's freedom of expression," Zhang wrote on his ifeng.com blog.

"We think the case could set a precedent as many Sina Weibo accounts shut down by the service provider," Wang said.

"It is right that Weibo accounts are shut down for specific reasons, but they should follow procedures only be closed as a last resort after warnings and penalties have proven ineffective," Li Shuming, a commentator with the Procuratorate Daily, said in an article published on January 9.