Germans usually don't define Berlin to be a "successful first-world major city" (saying that as a German)
So much for that...
Or is this merely a German joke about a rough town?
(Now I'm wondering if this is like the PRC, where Beijing has the rich history of a capital but bland areas like Shenzhen are where the money is made.)
The jokes about Berlin would be mostly about its horrendously mismanaged prestige project - the new airport.