does the Navigo pass cover the RER trains in central Paris as well. we'll need to get from CDG to Luxembourg RER stop where we will be staying across the street. would the navigo cover that trip from the airport? What areas does it cover as well as well as costs and are they available for any 7 days or just mon- Sunday. We will be arriving on Wednesday for a week. Please let me know any other options for the metro as well. If you can send a link as well to the Paris metro.