Night Train Cost with Railpass

A railpass pays for the rail part of a trip via night train. The accommodations on the train are an extra charge, often referred to as a reservation fee because in the process you reserve the seat, cochette, or compartment. If you find the connection on the German Rail website and click "check availability". That will show you a listing of the cost of each compartment at various fare types. Click on "book only extra charge" to see the cost of various accomodations with a rail pass. The extra cost of each type of accommodations is generally the same for any connection; what you are doing is renting the room.

Some overnight trains have cars where you sit in normal train seating (a tough way to spend the night) for the duration of the trip (or until the bar car closes) and these seats are covered by the rail pass. If you want accommodations for laying down like a compartment or a couchette then there is a supplement that has to be paid beyond the seat covered by the rail pass. Be aware that there are overnight trains which do not offer any sort of seating and you must buy a spot in a couchette or compartment to ride the train. You'll be given a separate ticket for the (say) couchette showing your room number and bunk space and you show this ticket to the conductor along with your rail pass. Overnight trains going into major cities like Paris often sell out quickly so I urge you to make your reservations ahead of time and not attempt to wait until the day (night) of departure before getting your tickets.

Thanks for the quick replies. So what would be the steps at reserving, say, the Vienna to Paris (via Munich) night train? The way I see it, we would take the train from Vienna to Munich and then transfer to the actual night train to get to Paris. I would already have used the railpass for the Vienna-Munich part of the trip that day, and since we fit into the 7pm rule, wouldn't need to use another day from the pass. When I reserve the Paris train, obviously ahead of time, I would tell the person taking the reservation that we have a railpass and only need to pay for the reservation for the train and also for the sleeping compartment. When we get on the train in Munich, we would show our railpass and our reservation and take our seats. Does that sound about right?
Thanks again for the help.

If you take the RailJet from Vienna to Munich and then the CNL night train from Munich, either all the way to Paris or Metz to Paris by TGV, that will take two days of your rail pass, one for the Rail Jet and one for travel after 7 PM with the night train. The 7 PM rule allows you to board a night train after 7 and not have to use a day of your pass up to midnight and a second day after midnight. However, there is a Euronight leaving Vienna at 19:48, with changes in Frankfurt (6:06) and Brussels. That route would take longer but only use one day of your rail pass. There would, however, be a surcharge for Thalys, Brussels to Paris. Or, once you get to Frankfurt, you could take an ICE or TGV directly to Paris.