A CPT makes €9000 (+ €1000 per diem) gross. He has to pay his own taxes where he lives. It is a commuting contract.
Let's say he lives in Sweden. Then he will cash about SEK 42,000. He will have 65,000 gross, and pay about 21,000 i social taxes on top of that. In all about 44,000 - or 51% - in total taxes.
But he is legal at least regarding his taxes...