According to a report we have just received from the ILAB [International League of Antiquarian Booksllers] the recently announced US tariffs on Chinese imports will apply to used, old and rare books as well new ones. This will even include books with only partial Chinese content and will apply to books imported from any country and produced at any period in time.
More details will be found on the ILAB website: https://ilab.org/articles/new-us-tariffs-chinese-goods-applicable-antiquarian-material
French language version is available here: https://ilab.org/fr/articles/nouveaux-tarifs-americains-sur-les-marchandises-chinoises