Train from Stuttgart to Paris

There's no reason to get a rail pass for this trip (or almost all trips). Just buy your tickets in advanced directly from the national rail companies (Deutsche Bahn, TGV, SBB, etc). If you can commit to riding at a specific time and date, you can save a significant amount of money. "I'm not sure if I'll go direct, or stop in Geneva on the way." Is that because you want to stop in Geneva? Because Geneva is considerably out of your direct line of travel. Trains between Stuttgart and Paris probably route through Mannheim and Saarbrucken, both of which are nowhere near Geneva.

You can book STR to Paris 92 days out on the dbahn website. 3hr40min with quick stops in Karlsruhe, Strasbourg, then straight on to Paris. Stuttgart to Geneva is 5-6 hrs and you have to change trains in Zurich and it's not on the way at all.

www.bahn.de is the best site to help you see routes, timing and pricing. You can buy your ticket here,and if you buy in advance you can get some great deals.

"You can book STR to Paris 92 ..." STR is the Stuttgart airport. I doubt that he is going to spend his whole week at the airport, but there are direct trains (usually TGV) from Stuttgart Hbf to Paris. When looking up schedules and booking with the Bahn, the homepage, Bahn.de, does get you started, but you will eventually be routed to this page, which allows you to input more information. I suggest you go there to start with.

I'm waiting to hear back from people I know in Geneva. If they are available, I would like to stay with them for an evening or two on my way to Paris, even though it takes me out of the way.