legal ground
Article 22 of the Criminal Law
Lawyers' service fees, fees paid on behalf of clients and travel expenses for handling cases in different places shall be uniformly collected by law firms. Without permission, a lawyer may not charge any fees to the client.
In addition to the three fees listed in the preceding paragraph, law firms and lawyers may not charge other fees from clients in any name.
Article 28
Citizens, legal persons and other organizations may report and complain to the price department, the judicial administrative department or the lawyers' association through letters, telephone calls and visits if they think that the law firm or lawyers have price violations.