I beg to differ. I was in Vienna for 4 days and it's quiet and boring as fuck. Unless you're super into looking at pretty buildings, I suppose.
Night life is non-existent, the place looked deserted - I was told you need to "know where to look", which is like, great, exactly what I expect from a capital.
It seems like 70% of the city's activity is to meet up with your retired neighbours for coffee and cake at 5pm and then everyone's gone to bed by 7.
German cities are FAR better. Just go to Munich if you want the Austrian feel. They're kinda related. But at least it doesn't look like a ghost city after sunset.
As for France, feel free to go to Clermont-Ferrand but don't blame me for it

I'd personally suggest Toulouse, Bordeaux, Montpellier if you want to stay south. Marseille is

and Nice is meh.
North, Lille is great, and at the crossroads of UK, Belgium / NL and Paris. You can get to any of those places super easily with the Eurostar

London is 1.5h, Paris 1h, Amsterdam is something like 2h away, I think.