Is it tax-free to pay domestic patent fees abroad?

No, when foreign countries pay domestic patent fees, they need to withhold and remit the value-added tax of overseas units at the rate of 6% according to the "sales of intangible assets", so they are not exempt from tax. Patent fee refers to a certain amount of royalties paid to the patentee by the licensee other than the patentee and the consumer of the patented product when using the patent and product.