[ivan1783]

I think a better term would be a 15m neighborhood, rather than city. I live in Stuttgart in Germany and there is no way that you can walk this city in 15m, however my neighborhood has everything I need (store, bank, pharmacy, doctors, dentists, hair cut places, kindergarten, school, metro station, train station, etc) within 10m walking from my house (the food shop is 700m away - the furthest of all). This becomes even more apparent in a city like Paris, it has its own quarters where everything is locally available - you don't need to cross the city to reach anything because its all already available in your quarter.

[Doctor_Fegg]

Yes, "15-minute neighbourhood" is certainly the phrase used in UK urbanist circles.