I have read both English and French versions of most Diskworld books. It is the best translation I have read, ever. Patrick Couton is outstanding. He carries all the charm and wit across languages, but is never a slave of Pratchett’s words and does not hesitate to adapt what needs to be. His French puns are glorious. Guet des orfèvres for Pseudopolis Yard is absolute genius, and so are many others. They always land well and are never jarring, and I find some of them better than the original. The Ch’ti that the wee free men speak is great. He managed to reproduce the difference in tone of the book series as well. Including the footnotes, which is most impressive.

TL; DR: if there is one good translation, it has to be this one. If you read it in French, you are not losing much over the English original.