Continue to work in China.

Hello,
I'm a recruiter with a "temp" working in China since April 2012. now his company want him to stay for another 12 months. Can I apply for the correct paperwork or is that the responsibility of the client based in China that he is working for. All parties with the current arrangement to continue.
also if he stays their what is his tax situ, currently as he is a French national he pays his tax in France.
Thank you for any help or guidance.
chris