Thank you Nishadha and Robert for your good advices.
I will pay attention to directories, improve content, read moz seo guide and also be patient...
I have just one more question about yyy (yes, the url is written with 2 "-")
It's not exactly a "competitor" website (because it's in paris, and i'm not in paris), but I don't understand why this site was first a few days ago for keywords "psychologue" "paris"... ?? Now it seems to be on the second page ...