I’m reading this as housing boom in the 70’s and 80’s, Paris needs new housing, and people are moving to the west.
They do have catacombs. They could build a city under the city, with multiple levrls of streets!
Paris doesn't need new housing, it just needs to keep upgrading its existing apartments :)
Otherwise yes sounds right.
Unequal bins lead me to wonder if they were cherry picked to tell a specific story. #howToLieWithMaps101
They correspond to the larger eras in French economy.
1946-1970 appears to be high density housing. 20% and just small squares peppered around urban centers.