Believe it or not, Paris. Tokyo is just too hectic. Were this asking about a smaller Japanese city instead, my answer would be different.
Which city in Japan (if not Tokyo) would you want to move to? My personal preference is Osaka -apart from all the other reasons (culinary not least of them), that is the only other city in Japan with which I have some familiarity from the years I lived in Japan.
The cities with which I'm familiar that I'd want in live in most are Kyoto, Aomori, and Hakodate, in no particular order. (I know Aomori has a reputation for not having much going on in it, but I really liked it.)