Can lawyers use their clients' special authorization to harm their interests?

Lawyers cannot use the special authorization of their clients to harm their interests.

People's Republic of China (PRC) Lawyers Law

Article 40 A lawyer shall not commit any of the following acts in his practice:

(3) accepting property or other benefits from the other party, and maliciously colluding with the other party or a third party to infringe upon the rights and interests of the client;

Article 49 If a lawyer commits any of the following acts, the judicial administrative department of the people's government at the municipal level or municipality directly under the Central Government with districts shall give him a punishment of stopping practicing for more than six months but less than one year, and may also impose a fine of less than 50,000 yuan; Illegal income, confiscate the illegal income; If the circumstances are serious, the judicial administrative department of the people's government of a province, autonomous region or municipality directly under the Central Government shall revoke his lawyer's practice certificate; If the case constitutes a crime, criminal responsibility shall be investigated according to law:

(5) accepting property or other benefits from the other party, and maliciously colluding with the other party or a third party to infringe upon the rights and interests of the client.

Measures for the Administration of Lawyers' Practice (DecreeNo. Ministry of Justice 1 12)

Article 33 When undertaking business, a lawyer shall guide his clients to claim their rights and settle disputes through legal channels and ways, and shall not incite or instigate their clients to take illegal means such as disturbing public order and endangering public security to settle disputes.

A lawyer shall not take advantage of the convenience of providing legal services to seek the disputed rights and interests of the client, accept property or other benefits from the other party, or maliciously collude with the other party or a third party to infringe on the rights and interests of the client.