Well, there’s http://json.org/ and it’s available in French. Regrettably I don’t speak French. I tried learning it once.
If you’d like info on REST API design there’s the API-Craft Google Group https://groups.google.com/forum/?fromgroups#!forum/api-craft
If you need to communicate between a web server and a browser I suggest giving http://backbonejs.com/ a try.
If you need to consume someone else’s API, I suggest finding a good REST client library for your server side platform. For node I suggest https://github.com/mikeal/request and for python I suggest http://docs.python-requests.org/en/latest/index.html Or, if you can find a specific API client that’s good, use that.
Best of luck! – Ben