Legal analysis: Generally speaking, it is not illegal, as long as the person who introduced the work is qualified. The percentage of commission depends on the content and profit of the project. The commission for fire fighting and intelligence is higher, and the profit can be less than 10% when it is about 30%, and less for civil engineering. The profit between 12 and 15% can only be 1-2%. Commission is generally allocated according to the progress of the project, but it should be collected in full after the final accounts of the project, and the quality guarantee money is for the construction party.

Legal basis: Civil Code of People's Republic of China (PRC).

Article 961 An intermediary contract is a contract in which the intermediary reports to the client the opportunity to conclude a contract or provides media services for concluding a contract, and the client pays the remuneration.

Article 962 The broker shall truthfully report to the client the matters related to the conclusion of the contract. If the broker intentionally conceals important facts related to the conclusion of the contract or provides false information, which harms the interests of the client, he shall not ask for payment of remuneration and shall be liable for compensation.