When you save tags (for example, with the Save button or with Ctrl+S), a popup appears to inform the user on the progress. In English, the title of this popup is "Writing tag data". In French, it is "Ecriture des informations tags... {} sur {}". It looks like a copy-paste error from the content of the popup, which is "Ecriture des informations tags... 6 sur 9"
The fixed version would be "Ecriture des informations tags".
And, while I'm at it, "informations tags" isn't correct French - at least I don't think it is. Since "tag" alone is used in many other places, like for example "Enregistrer les tags" or "Tag -> Nom de fichier", I think the popup title should be "Écriture des tags", and the popup content should be "Écriture des tags... 6 sur 9".
And since talking about the text in this popup made me notice the missing acute accent on the uppercase E, there's also one missing in the Edit menu, which should be "Édition" instead of "Edition" (if you care about a bit of background on that one, the French keyboard suck and doesn't have a way to type an uppercase é, even though it's extremely common in French. So it's acceptable, but not recommended, to omit the accent on uppercase letters that should have one).
Reproduced on the latest development version (v3.22d). Here is a screenshot with both the popup title and the Edition menu highlighted.
