Yes, your client's permission is required. This is the case regardless of whether the catalog is sold or offered for free. That's because when an artwork is sold, the buyer only acquires ownership of the physical work, for example, the framed painting. As the Seventh Circuit held, “a copyright is not transferred automatically with the transfer of the copyrighted good [thus] when you buy a book, you don’t obtain the right to make and sell copies of it.” The copyright (the right to display and make copies) is typically retained by the artist. There are exceptions to this rule, for example, if the artwork is a work made for hire, or if the artist assigns copyright to the buyer, but otherwise, the artist controls the duplication. BTW, the same rules apply for non-fungible tokens (NFTs). So, if your client creates an NFT, an NFT buyer would not acquire copyright.