To toggle the default language of the site from English to French, you will need to adjust your browser settings.
Open the menu on your browser and select Settings From the Settings menu, select Advanced, then click on Languages. Locate the default language on your browser, and click on the dropdown menu to expand the field Select Add Languages From the Add Languages menu, use the search feature to locate the language you wish to switch the browser to. Click the checkbox next to the language, then select Add. Click on the 3 dots next to the language, select Display browser in this language, then select Relaunch to apply the changes.