Legal basis: Civil Code of People's Republic of China (PRC).
Article 122. If another person obtains improper benefits because he has no legal basis, the victim has the right to demand that he return the improper benefits.
People's Republic of China (PRC) Civil Procedure Law
Article 3 The provisions of this Law shall apply to the people's courts in accepting civil lawsuits brought by citizens, legal persons, other organizations and among them because of property relations and personal relations.