Hello fellow flâneur! Though you won’t get the same level of safety, I definitely recommend Paris as a destination to walk around. The city feels like a museum and you can end up finding all sort of random monuments and beautiful architecture along the way. Also some cool street art. Obviously use common sense and you’ll be fine.
PS: I did Tokyo quite a lot, Shanghai too, though you usually need to take the metro at some point. San Francisco is also great if you don’t mind the hills (and also use common sense).
You're talking about digital walking, or real walking? I real-walked in Paris by night (around Moulin Rouge) and it was definitely a memorable evening. Taking a boat trip by day was also museum-like.
I agree, Paris is wonderful for either in-person or virtual walks. Most cities have large pockets of uninteresting zones, but Paris rarely has that. In the dozens of times I've been to Paris in my life, I have usually found a whole new cool small street that is often just 20 meters off a more trodden street. My obvious technique is to pick two points in the city and try to walk as direct as possible between them, forcing myself down side streets instead of walking down some grand boulevard for an hour. -- as I walk I'll put a star in my Google Map on anything interesting that I find so next time I'm in the area I can see that it is around the corner.