Constantinus Albertus Josephus Maria (Constantijn or Tijn) Kortmann (Groesbeek (Netherlands), March 14, 1944) is a Dutch professor of constitutional law.[1] In 1967, he obtained his doctoral’s degree in Dutch Law at the Catholic University of Nijmegen (nowadays: Radboud University Nijmegen). In 1964, he studied the French language for half a year at the Institut Catholique in Paris, France. After his degree he pursued his study of the French language, as well as French public law, for another year at the University of Poitiers. In 1976, he obtained his doctor's degree (master) at the Catholic University of Nijmegen. From 1976 to 1981, Kortmann was a professor of Dutch and comparative constitutional law at the University of Amsterdam, since 1981 he has been a professor of constitutional law and general political science. Furthermore he has been a dean of the Faculty of Law, twice in Nijmegen and once in Amsterdam. In 2004 the KNAW (Royal Netherlands Academy of Arts and Sciences) entitled him with an academy professorship.
The handbook Constitutioneel Recht (Constitutional Law, for which Kortmann received the Thorkbecke Prize in 1996), Het staatsrecht van de landen van de Europese Unie (Constitutional law of the Member States of the European Union), and Het bestuursrecht van de landen der Europese Gemeenschappen (Public Law of the Member States of the European Communities) are amongst his most important publications. The latter two books were edited by Kortmann in cooperation with professor Lucas Prakke.
In 2005, the second chamber of the Dutch parliament appointed him to be the chairman of the referendum committee on the rejected Treaty establishing a Constitution for Europe. This committee summarised the Treaty text and divided allowances between the advocates and adversaries of the Treaty.
Kortmann’s brother, Sebastiaan Kortmann, is a professor of Dutch civil law, and since May 10, 2007, the Rector Magnificus of the Radboud University Nijmegen.
Kortmann is asked regularly to give advise and explanation in matters of public law in Dutch media.