The domain your website is under (perso.wanadoo.fr) has about 5 million pages indexed in Google:
http://www.google.com/search?q=site%3Aperso.wanadoo.fr
And you've got about somewhere around 13 backlinks that actually point to your main page:
http://search.yahoo.com/search?p=lin...rso.wanadoo.fr
I would guess that Google changed their algorithm slightly and your website started getting lumped together with all the other content under perso.wanadoo.fr
Doing some link building with "garipiere" as part of the anchor text may be enough.
I would think the most effective thing to do would be to move your website to its own private domain instead of sharing your domain with lots of other websites.