Concept of principle of proportionality and its application in the jurisprudence of european union court of justice

In this work the concept of principle of proportionality was analyzed and how the mentioned above principle has historically progressed since the ancient times. A huge impact regarding the content of proportionality principle develpment had Germany, since in this country the proportionality test and its elements have been applied for 50 years already. Also, in this work, the concepts of proportionality, such as double proportionality test are discussed. Later, it examines how the proportionality test is applied respectively by the ECJ and the ECtHR and how the elements of test are specifically assessed, for example, the ECJ sometimes applies not the full test but only its elements - adequacy and necessity. In this case, when the proportionality test is applied, the ECJ also takes into account the actions of which subjects are being examined (Member States or EU institutions) in order to choose the intensity and detail of test accordingly. On the same note, the work reviews the recent tendency in the application of the principle of proportionality and compares how the principle is interpreted in similar cases. Analyzing the application of the principle of proportionality in ECJ case law in relation to the protection of personal data, it shall be noted that the principle of proportionality is mainly used to help find balance between different fundamental rights. Examining how different fundamental rights and the principle of proportionality are balanced, it should be stated that the ECJ gives more discretion to the member states, in case the case concerns health care. Nevertheless, the restrictions imposed by the Member States must be proportionate and the least restrictive measure shall be chosen, and it must be ensured that the measures taken are not discriminatory