Given a choice which among these two will you suggest? Which one is more scenic and has changing landscapes? They are almost same travel time; via Geneva takes little longer. Thanks.
(1) Interlaken-Bern-Geneva-Paris
(2) Interlaken-Basel-Strasbourg-Paris.

Geneva goes to Gare de Lyon the other to Gare de l'Est if that makes a difference - otherwise IMo the Geneva line may be a tad more scenic as it goes thru Burgundy, prettier to me than northern France. but the Basel line goes via the fairly new and world-record setting speed train line the LGV-est - more modern trains and up to about 190 mph, about the same as the Geneva route though I guess.

I'd take whichever one you find is cheaper. If you have a Swiss Pass there are some Pass 2 fares available that give you a discount trains to Paris.

interlaken - gstaad - geneva - lyon - paris. this route is very good. if you are traveling by car don't miss gstaad, you have the alpine glacier its amazing. then you can proceed thru geneva and take a night stay at any lyon hotel they are cheap and very good and then proceed towards paris.

Thanks guys.
@PalenQ: Yes, Geneva-Lyon too has highspeed line for part of the segment. Perhaps I should stick to scenic burgundy country as you said. I have eurail pass so either way I pay only for reservation and doesn't matter which terminus I reach.

@Edwin: Actually I want to be in Paris in 5-6 hrs so it will be Interlaken-Speiz-Bern-Geneva and not through Gstaad (which is a narrow gauge line). Interestingly, I will be in Gstaad a day before in Goldenpass panaroma/Interlaken-Montreux trip, even booked CHF15 front row VIP seats.

srini - I heard that you could pay more with a pass on the LGV-Est line as they may have two tiers of passholder fares - but on the TGV from Geneva only the 3 or 4 euro fare. In any case IMO make this reservation as soon as you get to Switzerland as railpass seats are limited in number on French TGVs - wait too long and you may not be able to get on the train you want even if that train is not full! Alas!

PalenQ, I am grateful to you for your timely advise. I never knew about the limited number seats for Eurail passholders. Somehow I started checking this morning (raileurope.com) and you're right. Basel-Paris costs USD22 (1class) but Bern-Paris also costs USD25 (2class and thats only available). Went ahead and bought Basel route for $22 as a friend is joining at Basel and there is no choice now.

We will be travelling from Rome to Switz a week earlier. Same story there too both in Milan-Brig-Spiez and Milan-Zurich Gothhard routes. The passholder's reservation fares I saw 2 weeks ago are NOT there anymore. Atleast lucky enough to see USD16 seats (1class) for Milan-Zurich and I just bought them. Will figure out how to get off in Aarth-Goldau and catch train to Luzern and then to Interlaken (perhaps in Goldenpass panaroma).

Wow! this is so challenging but I love every part the planning now.