Criminal law covers the rules and principles of criminal offenses, criminal liability and penal sanctions. It is related to all other branches of law. The fundamental principles are the principles of human dignity and humanity, the principle of legitimacy and repression limited to cases where the protection of man or other fundamental values can not be guaranteed otherwise, the principle of legality, the principle of subjective liability and fault, and the principle of proportionality between a crime and a punishment. In a broader sense, criminal law also covers disciplinary offenses and misdemeanours.

The lawyer defends the perpetrators and the accused or represents the aggrieved parties as plenipotentiary in various procedures of criminal law (pre-trial, criminal proceedings, misdemeanour procedures, court misdemeanour procedure, disciplinary proceedings, etc.). The lawyer represents his clients by direct representation before the courts and other bodies or persons as well as by way of written submissions, declarations, complaints – objections, requests for judicial protection, etc.