In its judgments, the Constitutional Court takes into account the case law of high international courts, such as the Court of Justice of the European Union and the European Court of Human Rights, which it frequently quotes.
Since its establishment, the Constitutional Court has submitted numerous preliminary questions to the Court of Justice. A section of the Court's website is devoted to preliminary questions referred to the Court of Justice. For example, in 2019, the Constitutional Court addressed 17 preliminary questions to the Court of Justice in four separate cases.
In addition, the Constitutional Court is a member of several networks or associations bringing together foreign, European or international supreme courts.
Since 1990, the Court has been a member of the Conference of European Constitutional Courts (CCCE), which brings together around forty European constitutional courts or similar institutions that are responsible for the constitutional review of acts. Congresses are regularly organised, in which the Court systematically takes part by sending a report on Belgium. In 2002, the Court organised the XIIth CCCE Congress, on the theme: "The relations between the constitutional courts and other national courts, including the interference in this area of the action of the European courts".
For more information: https://www.cecc2017-2020.org
The Court is also represented in the Joint Council on Constitutional Justice. Set up in 1990 by the European Commission for Democracy through Law (known as the Venice Commission), a consultative body of the Council of Europe, the purpose of the Joint Council is to organise co-operation between constitutional courts and courts of equivalent competence. It is composed of experts from the Venice Commission and liaison officers appointed by the aforementioned courts. Its work concerns not only the member states of the Council of Europe, but also around twenty other states, the European Court of Human Rights, the Court of Justice of the European Union and the Inter-American Court of Human Rights. In addition to the exchange of information and the regular organisation of conferences, this collaboration takes the form of the publication of a Bulletin on Constitutional Case-Law and a public database containing summaries of decisions handed down by the courts involved.
For more information: https://venice.coe.int/
The Court has been a member of the "Association des Cours constitutionnelles francophones" (ACCF), formerly known as the "Association des cours constitutionnelles ayant en partage l'usage du français" (ACCPUF), since its creation in 1997. It is a network of about fifty constitutional courts of the member countries of the "Organisation internationale de la francophonie". The ACCF endeavours to organise regular meetings between its members, enabling the exchange of ideas and experiences. It also organises training and legal and technical cooperation.
For more information: https://accf-francophonie.org/
The Court is part of the World Conference on Constitutional Justice (WCCJ), which brings together more than 100 constitutional courts, constitutional councils and supreme courts around the world. The WCCJ promotes constitutional justice as an essential element of democracy, the protection of human rights and the rule of law. Its main purpose is to facilitate worldwide dialogue between judges of constitutional courts, in particular through the organization of periodic congresses, participation in regional conferences and seminars, and the exchange of experience and case law.
For more information: https://venice.coe.int/
The Court is a member of the Superior Courts Network (SCN), which is a network set up in 2015 by the European Court of Human Rights (ECHR) to enable the exchange of information between the supreme courts of the Council of Europe member states. This network comprises almost 90 courts from 40 different states. At the request of the ECHR, the member courts send contributions on particular topics in domestic law, usually in connection with cases pending before the Grand Chamber of the ECHR. The member courts may also ask the ECHR about a particular issue. The ECHR also provides research reports or information notices to the member courts. The contact persons of the various courts meet annually on the premises of the ECHR in Strasbourg.
For more information: https://www.echr.coe.int/
Finally, the Court has been part of the Judicial Network of the European Union (JNEU) since its creation in 2018. It is a network for the exchange of information and judicial cooperation, bringing together about 60 national constitutional and supreme courts. The JNEU is implemented by a website managed by the Court of Justice of the European Union and accessible only to member courts. This site is maintained by the Court of Justice, but also by the national courts, which can download research notes or case law of interest to the Union. Part of the JNEU is accessible to the general public on the website of the Court of Justice.
For more information: https://curia.europa.eu/