Examination of tax evasion acts and penalties within the framework of propotionality and non bis in idem principles

The state imposes various sanctions on those who disrupt this order in order to ensure the social order and the order brought by the law. These sanctions sre regulated in all areas of law. One of te areas thet make up is tax criminal law. The legislator imposes two types of sanctions, administrative and judical, on taxpayers who acts ageinst the law. At the beginning of the tax penalty application, which is most suitable for discussion in the doctrine, comes the tax loss penalty and the penalty for tax evasion, and the two sanctions are cut separately. In study using, the literature review method, the evaluation of thr two sanctions applied in the case of tax evasion by causing tax loss in the context of propotionality non bis in idem principles is discussed. The principle of proportionality states that at the stage of limiting a right or freedom, the means of restriction must be appropriate, necessary and proportionate to the purpose. The principle of non bis in idem refers to the prohibition of being tried and punished twice for the same crime. As the basis of the study, the penal policy applied within the scope of tax criminal law should comply with the principle of proportionality and non bis in idem which is a requirement of the rule of law. The proportionality analysis has been tired to be made by considering the state of both sanctions in abstract regulation and their deterrence and effectiveness in the concrete event, and by establishing a connection between the two sanctions in terms of the prenciple of proportioanlity and the principle of non bis in idem, suggestions have been made to ensure compliance with both principles.