Is it infringement to sell the products applying for patent for appearance?

As long as the design patent applied by the salesperson is authorized (the general design is easy to authorize), it is infringement for you to sell this product, including the manufacturer's production of this product. What you can do now is to prevent him from obtaining this patent by presenting evidence to the State Patent Office that he can't become a patent, such as pictures of products that he has sold in the market before applying for this patent, or pictures that he has publicized or advertised in exhibitions, periodicals and magazine media before applying for this patent. You can consult a lawyer for details.