The subject of this article is the analysis of reasons and results of determining as well as changing tax residence in the light of Polish personal income tax. This topic underlies a broad concept of migration, especially that of profit-driven character. The author presents this research issue on the basis of the current legislation, doctrine as well as practice of applying the law by the judiciary and the tax autho-rities. The analysis of the valid regulations of tax law leads to the conclusion that the fiscal situation of migrants is so diversified as well as complicated from the legal point of view that it raises justified practical doubts. It is assumed that tax residence is dynamic and thus may change as a result of both intended and unin-tended taxpayers’ actions which may have specific tax law effects. They are reflected not only in tax preferences but also in obligations concerning tax settlements. Apart from ordinary tax consequences of determining or changing tax residence, the author relates also to particular legal solutions such as: exit tax, taxation of foreign controlled companies or appliance of the provisions of Multilateral Convention (MLI). The described issues are significant for both theory and practice of tax law application.

Introducing Article 22, section 9b, item 1 into the Personal Income Tax Act of 26 July 1991 using terms that have not been defined in this Act and not specifying the provisions of other acts of law which would become the grounds for defining these terms, thereby creating a normative condition for applying 50% tax-deductible expenses to income arising from activities performed by IT employees, the lawmakers failed to observe the requirement of correct legislation determined by the Constitutional Tribunal in its judgements, creating a law that is vague and imprecise, and gives the entities applying it a sense of uncertainty about whether they apply the provisions of the Personal Income Tax Act correctly.

This article aims to show the similarity between the arguments developed regarding the Treaty freedoms and the approach to the legal principles proposed by R. Alexy. Treaty freedoms from the Treaty on the functioning of the European Union, developed in the course of the Court’s many years of judicial activity, have a number of similarities to the concept of the principles of law proposed by prof. Robert Alex. This is evidenced by – the position of the principles of law in the legal system, the possibility of grading them, or a separate method of resolving the conflict of two opposing principles of law. The article analyses selected treaty freedoms in relation to tax matters and compares them with theoretical schemas proposed by prof. Robert Alexy.

The article discusses the phenomenon of "tax carousels" in the tax on goods and services, which is a specific abusive practice and is used for VAT refund scam purposes. A discussion on the jurisprudential doctrine of the abuse of law and good faith as offered by the Court of Justice of the European Union is followed by an analysis of the judicial decisions (case-law) issued in this area, which proves that taxable persons involved in value-added tax fraud practice have no right to a tax deduction. Meanwhile, those taxable persons who have fallen victim to tax fraud practices may quote the good faith doctrine and exercise the right to a tax deduction. The judicial decisions of the Court of Justice of the European Union have had a significant impact on the judicial decisions issued by administrative courts in Poland. The Supreme Administrative Court (SAC) tries to define the notion of a "tax carousel" in its decisions, as the notion is quite broad.

The article addresses the issues of the stimulating (intervention) function of the betting and gambling tax. It attempts to answer the question whether the intention of the Polish legislator was to ascribe this function to the betting and gambling tax, and if so, to what extent such assumptions were reflected in the legal provisions and the resulting norms. The first part of the article identifies the basic levels of the performance of the stimulating function of the betting and gambling tax in theoretical terms. The second part presents the functions that were attributed to the lottery monopoly and the taxes that affected the organisation of gambling games in the interwar period and in the Polish People’s Republic. The third part of the article analyses the provisions of the Act on Games and Mutual Wagering as well as the Gambling Law in the context of the extent to which these regulations were expected to have an interventional effect at the drafting and adoption stage.