Edit: nvm, I found it another way ;)
If you consider the municipality population:
Rome: 2,869,461 vs Naples: 990,000 (2014 estimate)
If you consider the metropolitan population:
Rome: 4,321,244 vs Naples: 3,128,000 (2014 estimate)
(English version gives city proper only)
Should ve gotten zurich, glasgow and I guess naples too.
I did get essen of the ones that didnt score too high. Hadnt heard of the ujqx ones.