Earlier quoted context omitted.
There was another good interview in NYC on US premiere day: https://youtu.be/zH982kFXMuM I had to make sure to be in NY for it. Last time I saw him live (at IFC for The Zero Theorem), he mentioned that he can only spend 29 days per year in the United States after giving up his American citizenship. His days are counted, in a way...
Weird - this German language source [0] from around the time of his citizenship renunciation indicated the 29 day cap last for ten years - so it would've stopped 3 years ago.. [0] https://www.tagesspiegel.de/kultur/kopflos-am-potsdamer-plat...
https://www.irs.gov/individuals/international-taxpayers/expa...
He mentioned it in 2013. So he's probably not affected anymore, but he still tends not to spend a lot of time in the US.