when i visited Paris i stayed in Colombes, a “banlieu”. i stayed there, sure, because i could not afford to stay in central Paris. Colombes was undergoing an incredible construction boom, building on a scale that would be impossible in central Paris, without some kind of revolutionary consensus. 1/

Colombes was being developed at high density, via extremely attractive apartment buildings. (i was very jealous.) it’s 20 mins on the train to central Paris. as tourists we rode that every day. 2/

Columbes itself is absolutely a 15-minute city. it has a town center with a kind of main street, a square with nice restaurants, etc. 3/

does Columbes offer the full set of options of all the Paris metro area? by definition, of course, no (since it’s only one tiny sliver of that!) does it offer a quality of life comparable to central Paris? yes! 4/

there would be different trade-offs for different neighborhoods, but Columbes definitely has advantages that would compensate for its disadvantages, many people would find it preferable to many other fine (and affluent) areas. 5/

hypothetically, might it be better if all of Paris were a 15 minute city, if with the same geographic accessibility of Colombes itself one could access all the options of the Paris metro area? 6/

absolutely that would be better. but there is no path to that, none. 7/

when we are building de novo districts, we can make them as dense as possible to maximize in-district agglomeration benefits. and we should, absolutely, subject to livability constraints! 8/

but it is building such districts that is the only meaningful path to augment high-quality urban at scale. it is not feasible — and not only for disagreeable NIMBY reasons — to take the 15 minute city at the center if historical metros and just add all the housing you need there. /fin