Off Switzerland and Paris, its very difficult to choose as both are equally gorgeous. Visit both if budget permits. Eastern Europe is equally beautiful and would give you great places at reasonable rates. Check for Slovenia, Croatia, Prague, Montenegro. Apart from Europe Maldives, Mauritius, Fiji Islands and Bora Bora are also very good.
Both can be done in one trip. I am currently making a series on this topic. You can check out the 1st video here-https://youtu.be/n0Kve643AUg. Rest of them coming in following weeks. Hope it helps making up your mind.
As a resident of paris, for me definitely switzerland is more romantic compared to paris. You can spend a maximum of 2 days to cover the places in paris, so switzerland would be more romantic and there will be much to visit compared to paris. you can do both if you have a week time.