I wonder where Racedo (and Google's highest ranking for Copenhagen population) pick up their facts? Copenhagen is Scandinavia's city with the largest population. It has a higher population, somewhere between 2 and 3 times 580 000 (depending on whether you count urban or municipal).
Frank Jensen - Mayor of Copenhagen Municipality
Copenhagen Municipality - Wikipedia, the free encyclopedia
Just because a city has a large population doesn't mean people all work for the Lord Mayor nor does it mean he is in charge of it.
BoJo is Mayor of London but that doesn't mean public employees work for him or his office in London. Overwhelming majority in local Govt in London do not.