Is it illegal for developers to sell real estate and rent it back through a third party?

This is not illegal, and there is a lease contract.

"Residential Quality Guarantee" generally stipulates that the leakage of basement and pipeline is 1 year; Wall and ceiling plastering layer falls off 1 year; It's been 1 year since the ground was hollowed out and cracked and a large area of sand blew.

Cracking of doors and windows and damage of hardware and sanitary ware 1 year; Lamps and electrical switches are damaged for 6 months; The pipeline is blocked for 2 months; Heating and cooling system equipment is heating period or cooling period; The warranty period of other parts shall be agreed by the buyer and the seller themselves and written into the project quality guarantee.

Business qualification:

The Regulations on Qualification Management of Real Estate Development Enterprises stipulates that urban real estate development enterprises shall apply for the approval of enterprise qualification grade and hold the Certificate of Qualification Grade of Real Estate Development Enterprises issued by the competent construction department.

The Regulations on the Administration of the Qualification of Real Estate Development Enterprises divides the qualification of real estate development enterprises into five grades, among which the first, second, third and fourth-grade enterprises can engage in urban real estate development business, while the fifth-grade enterprises can only engage in the development and operation of village real estate in their own regions.

Examining the developer's qualification depends not only on whether the relevant documents are complete in form, but also on whether the developer has the corresponding development qualification in essence. For the sake of prudence, it is recommended that buyers try to choose real estate developers who are rated as first-class or second-class enterprises.

Baidu Encyclopedia-Real Estate Developers