to access Google Feed API using Node.js, you should try the google-feed-api module as explained here:
https://www.npmjs.org/package/google-feed-api
Hope it helps!
Edit:
I tried this with your URL and worked fine:
var gfeed = require('google-feed-api');
var feed = new gfeed.Feed('http://rss.lemonde.fr/c/205/f/3050/index.rss');
feed.listItems(function(items){
console.log(items);
});