If your blog's admin interface is in French, and you need to change it to be in English, begin by logging into http://blog.gandi.net

Then, click on the following icon that you will see in your admin interface:

…and then click on the dropdown language menu, and select “English”:

Then, click on the button on the bottom-left hand corner that says “Enregistrer” and you will see the changes take effect immediately.

To change the language of the blog itself (ex. the titles, buttons, etc.) click on the “blog settings” icon which will bring up a page that will allow you to select the language of the blog :