French law is divided into two principal areas: private law and public law. Private law includes, in particular, civil law and criminal law. Public law includes, in particular, administrative law and constitutional law. However, in practical terms, French law comprises three principal areas of law: civil law, criminal law, and administrative law. Criminal laws can only address the future and not the past (criminal ''ex post facto'' laws are prohibited). While administrative law is often a subcategory of civil law in many countries, it is completely separated in France and each body of law is headed by a specific supreme court: ordinary courts (which handle criminal and civil litigation) are headed by the Court of Cassation and administrative courts are headed by the Council of State.