From China Digital Space
钓鱼执法 (diào yú zhí fǎ): entrapment (literally: fish, then enforce the law)
Entrapment is when a law enforcement agent induces a person to commit an offense which the person would otherwise have been unlikely to commit.
Perhaps the most well known entrapment case in China is the case of Sun Zhongjie in Shanghai. Sun picked up someone asking for a ride. Though Sun did not request it, the man gave Sun money when he reached his destination. The man then revealed his identity as an under-cover police officer and detained Sun for driving an unlicensed taxi. Sun's conviction was overturned after an outpouring of internet pressure (see here).
For a discussion of other famous entrapment incidents in China, see here (Chinese).
The Sun Zhongjie case is parodied in the "War of Internet Addiction."