question about seating on TGV Thalia

Bob, train seats only partially recline, and you have a lot more leg space than planes, so it is not an issue.
The method of reclining is different. The seat back facing the person behind doesn't move. Instead the cushion you lean your back against slides down (within the seat), and at the same time the cushion you sit on slides forward. So the leg space it takes away is yours. To put it upright again, you put your feet on the floor and push back.
I hope that makes sense, difficult to explain.

Window views are also not an issue. The windows are large, and only have small pillars between them (think bus windows). The seat backs usually align with the pillars between windows.

This 360° view of a 1st class coach may help: https://www.360cities.net/image/france-tgv-high-speed-train-paris-barcelona-duplex-first-class-2012
And this video here: https://www.youtube.com/watch?v=KrXUqOPU9wc

With 2 people, I recommend getting one of the seats pairs facing each other across a table. then you can talk, share the table for a picnic etc.

Two final points:
1) Most people, including me, say that 1st class is unnecessary. 2nd class is perfectly OK, unless you get a cheap deal for 1st class.
2) Are you actually heading for Zürich? For many places in central Switzerland (Luzern, Berner Oberland etc.) you do not need to go all the way to Zürich. Change trains in Basel, and head from there to your final destination. Saves about 1 hour on going via Zürich.

Chris- you described it perfectly, those seats are called Incliners, where the front of the seat moves to allow the back to recline. No need for any space in the back.

Thanks Chris. That was a very clear description of how the seats work.
I've seen that video and the 360 degree photo. I didn't think either of them were definitive. And I have sat in train seats where the view out the window is significantly compromised by the wall. One time, my neck got sore from keeping my head turned at such a sharp angle. No fun in that.

Chris nailed it

To manage expectations, the scenery between Paris and Switzerland is nothing to write home about... Some rolling hills before Dijon, then it's fields, and quite a lot of urban-industrial areas and tunnels between Basel and Zürich.

Thanks balso. Good to know. When the scenery stops being interesting I'll use the incline function and take a nap.