By curiosity, do you have some of those examples of french translation ? The only recent one I can remember, is in the french translation of DanDaDan, when they botched Abba's Chiquitita song.
Late reply due of the recent festivities so my apologies for the delay. Happy New Year btw.
To be entirely fair, I don't really follow any French translation of japanese media these days. But I do recall from experience that it was most often changes in characters names such as in One Piece where Sanji -> Sandy and Ussop -> Pipo (a french pun word to say someone is proudly lying) until the late 2000's when the editors reverted back to the original Japanese names and the book publisher (Glénat) had to reprint all the previous manga volumes to this effect. Steam Detectives, my first manga serie, had the nurse heroine renamed as 'Clochette' (instead of Rinrin) although the boy detective remained as Narutaki, but the translation abruptly stopped at volume 5 for whatever reason.
Old anime from decades ago had similar changes too: Grendizer -> Goldorak, Captain Harlock -> Captain Albator, Captain Tsubasa -> Olivier & Tom, Lupin III -> Edgar, City Hunter -> Nicky Larson, etc. Nowadays both the original and localized names (for the older baguette audience now in their fifties or sixties) are used for these series.
Hokuto no Ken was the worst offender in terms of French localization iirc, but that serie also sparked a whole debate on cartoon violence in the late 80's. Back then in France, people responsible of TV programming in national channels bought entire catalogues of Japanese animations at low costs without bothering to look at their contents in the first place since the late 70's. In 1988, HnK aired for the first time in France (through a kid's show
Dorothee's Club as the default platform for anime) with a dubbing cast that changed a lot of lines and Japanese lingo to make it look sillier in order to counter the amount of portrayed violence (the famous "You're already dead" quote was still there at least). Although this didn't stop the anime to be progressively censored because of the public reception back then.
The sole mangas translated in French I purchase nowadays are meant to be gifts for my young relatives (such as Spy x Family or One Piece), I admit I didn't have the curiosity to peer inside and compare with the volumes in Japanese I buy for myself. Besides the ability to read them directly in moonrunes, I also paid half the price for serialized volumes from Japan.