most scenic trainride Interlaken to Paris?

There are many options, but via Geneva-Lyon could be a scenic option.

you would have to work hard to cobble together a series of TER trains if you want to hop on and off.

The usually used TGV trains are fast and do not stop much, and you can't just get off one and onto another.

If you are hoping to do this with a railpass you should know that in France every leg needs to be reserved, and there are high, mandatory, and sometimes sold out, railpass reservation fees for each leg in addition to your railpass.....

Sounds like we are best off just grabbing the direct train and making the most of our time in Paris!

Search Bahn.com Interlaken to Paris adding Bern and Geneva or Geneva and Dijon as layovers (toggle more options to get layovers)

Under 7 hours and probably more interesting scenery, see Lake Geneva etc. Expand individual legs to see actual stop by stop routing, then check against Google maps or openmapsrail.

I think a little digging might be worth your while, not unacceptably slower or unacceptably more inconvenient than the standard route to Paris. Get up early and visit a couple of places along the way :)

Actually the French countryside between Paris and Switzerland is nothing special. I would not go out of my way to see more of it. Just take the fast train and spend more time enjoying the scenery around Interlaken, or in Paris.
(I did that route 6 timed last year, and will do it at least 2 times more in the next months. I know it well. It is boring. Making it longer will not make it more exciting...)

I agree with Wengen.

Generally train tracks are laid in flat rural areas where they can get the land cheap. This is especially true for high speed rail which needs to be straighter for the high speed, and was added later when land was more expensive and more developed. Check the rail connection from Bordeaux to Toulouse or Clermont Ferrand to Lyon .... short distances on a map ... but because of scenic mountains, you have to go all the way back up to Paris, then back down if you want high speed train.

So it's rarely if ever scenic to any significant degree. And when you see some river or mountain, you're traveling so fast that by the time you pull your phone out, it's past. None of your photos looks very good because the double windows always have a bunch of reflections from interior lights.

I have taken trains and driven between Paris and Strasbourg, and Paris and Lyon, and the scenery is nothing to write home. In the north, it's essentially rolling farmland, and roughly the same Lyon to Paris. There are some scenic seaside areas along the Med (the Nice to Menton route passing Monaco and cute port towns and high hills, and the Barcelona to Nimes route with some views of lagoons full of wild pink flamingos)

The beauty of high speed rail is having more time on target. When you get from Paris to Bordeaux, or Paris to Lyon in 2 hours as opposed to 6 hours of driving, then you can get one meal in one town and the next in the next city and go on your way. I have driven from Marseille to Paris and it took an entire long day, but when I took the train, I was surprised when we arrived - expecting we were only half way there.

• The exception to this is Switzerland - where everything costs twice as much - the place is very scenic - and they have cities in scenic areas so they have invested billions on exotic rail - which can be jaw-dropping expensive in the most scenic areas.