Sales are related to patents, and sellers are subject to patent supervision, as follows:
Article 11 of the Patent Law of People's Republic of China (PRC) (revised in 2020): Except as otherwise provided in this Law, no unit or individual may exploit the patent without the permission of the patentee, that is, it may not manufacture, use, promise to sell, sell or import its patented products for the purpose of production and operation, nor may it use its patented methods and directly use, promise to sell, sell or import them according to the patented methods.
After the design patent is granted, no unit or individual may exploit its patent without the permission of the patentee, that is, it may not manufacture, promise to sell, sell or import its patented product for production and business purposes.
As can be seen from the above, sales behavior is restricted by patent law.