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I am interested in over 600 USD treshold check payouts particularly....
The revenue you get from Google is Income for you. That means you have to pay income tax (percentage depending on your personal situation).
The $600 treshold may be important for US based publishers, but here you simply bring your check to the bank and pay those ridiculous high fees (I am paying €23,- for each foreign check).
The treshold you may want to worry about is €25.000,- then you will be subject to anti-money-laundry monitoring (Geldwaeschegesaetz).
However, being a good citizen you probably have your company registered with the authorities and therefore have a Tax-ID - leave the worries to your accountant and keep building your business :,)