Good afternoon. I work as a CM in a Dutch company and also worked in 2020 as a part-time worker in a company in the Russian Federation. Income from part-time work is small - less than 10000 € per year after deducting tax in the Russian Federation. Do I need to declare this amount? If yes, then how? How does the Dutch tax office find out about my income in the Russian Federation? What is the liability for not reporting this income? Thank you in advance!