Switzerland is of course in there, maybe Netherlands, maybe Belgium, not sure about Denmark, certainly not France nor Germany. Rail transport outside of Paris which does not involve the TGV is absolutely crap, meaning expensive (unless you purchase your tickets 3 months in advance or some crazy stuff like that) and it doesn’t get you to where you want, unless you want to get from Paris to one of the big other big French cities, but in that case you’d take the TGV anyway.