In 1999 I was earning $135k from a US-based job while I lived in Italy. Thanks to the tax treaty, I did not pay US income tax on the first $85k of that, but I paid Italy for it. I paid BOTH COUNTRIES on the remainder. Lost over 55% of my income to taxes that year. I was not thrilled that a lot of it was going to the Berlusconi government.

I'm told (by tax specialists) that nowadays the situation is that you pay the taxes in whichever country has the higher taxation rate, but nothing in the other country. That will be fine - I'm ok with paying higher taxes when I'm getting better services, like a good public health system that works for everyone.