[iggldiggl]

The Paris example is somewhat skewed, though, because Paris proper is comparatively tiny – just 105 km² and 2.1 million inhabitants. Compared to London it's basically just Zone 1 and a few bits (definitively less than half) of Zone 2.

Having said that, yes, it could still well be (too lazy to figure it out properly) that inside this city core the Paris Metro is still more dense than the Underground in London – but on the other hand beyond that, where the vast majority of inhabitants of the whole urban agglomeration of Paris live, you have similar problems regarding radial travel as elsewhere:

https://www.ratp.fr/plan-de-ligne/img/rer/Plan-RER-et-transi...