I purchased this book along with all the other Potter books in French as part of my attempt to learn French some 40 years after high school. I had read the English and Spanish versions previously and found this and the other FRench volumes to be delighful although it took a little getting used to name changes for places and characters that probably made sense for francophiles but seemed unnecessary -- unless the french language versions of the movies also had the changes.

That said, the books have been a great aid in language learning. The translations seem pretty capably done insofar as keeping the story line anchored to the original. I have seen many book translations (such as the Fernch version of The DaVinci Code) that are not faithful to the original in many respects such as cutting out dialogue and scene descriptions.