As Dan said there will be a high speed train soon.
Currently, the best route would be taking the train that leaves Rothenburg ob der Tauber Bahnhof @ 06:57 and arrives Paris Gare du Nord @ 16:05. It does not run on week-ends - click days of operations. Duration is 9 hours 8 mins.
You change at Steinach & Wurzburg & Koln (Cologne)at Koln you take the Thayls which is a fast train and you must have seat reservations.
Steinach & Wurzburg are small stations.
Once you have decided which train you want - print out the details.
That way you will know all your stops, arrival platforms and departure platforms.
Familiarize yourself with this Die Band site.
Enter from: Rothenburg ob der Tauber to: Paris.
Change the date ahead a few days, change the time time 06:00 click Search Connection, enter an age for travelers..click Search Connection again.
You can click Later as many times as you want to see later trains.
You can hover over the Station Stop of the trains.