I don't remember what happens with Elements 6 or whether it was available in French, but I suspect that it was an option. The language choices since at least Elements 11 are made in the initial steps of the installation. So, if you currently have Elements 6 installed on your machine, it would be necessary to uninstall it, then install the program again. If French is available, it should be one of the first options you are asked to choose during the installation process. However, having said that, you may have problems installing Elements 6 on a recent computer.
I am happy to still have PSE6 working on my current W10 computer. It's the English version from a specificUS-English version CD. I suppose you have the same CD with its particular license number. All the contents of the CD are in English, so I don't believe there is a possibility to change the language as you could do with more recent versions. Also, be sure to have a copy of your CD and license number if you want to reinstall PSE6 on another computer: success in reinstalling on a new computer and OS is not guaranteed.
Merci pour votre réponse mais je n'ai aucun problème avec ce programme qui s'est installé correctement sur WIN10 (sans mode compatibilité) sur mon Asus de 4 ans.Le fichier language n'est pas sur le cd, je ne sais pas, par ailleurs, s'il en existe un.Je vais devoir faire des progrès en anglais