Design patent: a new design of a product's shape, pattern, color or their combination, which is aesthetic and suitable for industrial application. The new design can be a graphic design of lines, patterns or colors, or a three-dimensional modeling of the product.
The patent laws of Hongkong and Chinese mainland are independent of each other. If the design patent is novel in China market, you can apply.
Handicrafts and stationery with beautiful shapes can apply for design patents.
If someone else used it first, and when you apply for a patent, you don't have the new doubtful requirements of the patent, the patent office can grant the patent, but strictly speaking, the patent you applied for is invalid.