Bonjour If you do not have the Firefox user interface in French then you can install the French Firefox version. You can find the full version of the current Firefox release (78.0.2) in all languages and all operating systems here: *https://www.mozilla.org/en-US/firefox/all/#product-desktop-release *https://www.mozilla.org/en-US/firefox/78.0.2/releasenotes/ ---- You can set the preferred language for web pages via "Options/Preferences -> Général -> Langue et apparence -> Langue -> Choix de la langue préférée pour l’affichage des pages".<br>You can seqrch the Add-ons website for a translate extension to translate pages that aren't in French. *https://addons.mozilla.org/en-US/firefox/search/?type=extension&q=translate ---- See also: *https://support.mozilla.org/en-US/kb/use-firefox-another-language *https://support.mozilla.org/en-US/kb/choose-display-languages-multilingual-web-pages