There are diverse law systems in the world. At least, five law systems known in the world are civil law system, common law system, customary law system, Islamic law system, and mix law system. Indonesia's law system is civil law system. The civil law system is the law system that refer to written rule. The binding force in civil law system is come from codification or compilation of written rule. Legislature institutions are very important in Indonesia because they have authority to establish and enforce the Act as written rule. The legislatures in Indonesia are the House of Representatives (DPR) and the President.
The classifications of the law in Indonesia are consisted of public law and private law. Public law is the law that relate to public interest such as the relationship between citizens and the state, and public service. Public laws in Indonesia are criminal law, administrative law, and constitutional law. Whereas the private law is law about relationship between human beings, between one person and another person with a focus on individual interests. Private laws in Indonesia are known as agrarian law, business law, commercial law, and intellectual property rights.
Indonesia's law system applies the norms hierarchy theory of Hans Kelsen and Hans Nawiasky. Based on Article 7 of the Act Number 12 Year 2011, the hierarchy of legislation in Indonesia consists of (i) 1945 Constitution; (ii) MPR’s Decree; (iii) Act or Government Regulation in Lieu of Act; (iv) Government Regulation; (v) Presidential Decree; (vi) Provincial Regulation; and (vii) Regulation of the Regency or City. When the Act is contrary to the constitution, the Act can be applied for review to the Constitutional Court. Beside constitutional review, Indonesia’s law system has procedure of judicial review by Supreme Court. Judicial review is the authority of Supreme Court to review legislation under the Act like Government Regulation and Provincial Regulation.
