You must set your browser to language
For Internet Explorer:
Tools > Internet Options > click [Languages] button near the bottom.
If you cannot see French (France) [fr-FR] in your list, simply add it by clicking the [Add...] button, choose it from the list and click [OK].
French (France) [fr-FR] needs to be at the top of your list. If it isn't, select it and click the [Move Up] button until it's at the top.
Click [OK] to save your settings and close the Languages box.
Click [OK] to close the Internet Options box.
Hold [Ctrl] and press F5 to reload this page. If the warning disappears you can now log in safely.