Article 17 transmission to minor children

This route covers the transmission of Belgian nationality to a minor child (under 18) under Articles 17 to 20 of the Code de la nationalité belge (CNB), the Loi du 28 juin 1984 (M.B. 12 juillet 1984), as subsequently amended. It is a derivative descent pathway: the child does not apply on the basis of birth alone, but acquires Belgian nationality as a consequence of a parent's own acquisition of that nationality.

The core mechanism is set out in Article 17. When a parent acquires Belgian nationality, a minor child automatically acquires it as well, provided the child is residing with that parent at the time of acquisition. Article 18 governs the retroactive incorporation of children into the parent's acquisition. Where the conditions for automatic acquisition under Article 17 are not met, Articles 19 and 20 provide a declaration-based route, allowing the parent to extend Belgian nationality to the child by declaration during the child's minority.

Belgian nationality is an exclusive federal competence (Constitution, Article 8), governed uniformly by the CNB across the country. In practice, an eligible applicant files a declaration with the municipal civil registrar in Belgium, or through a Belgian consulate when abroad. The route is administered by the civil-status authorities (the officier de l'état civil at the municipal level), and operates in the country's three official languages — French, Dutch and German — according to the relevant linguistic community across Flanders, Wallonia, the Brussels-Capital Region, and the German-speaking Community.

This route is governed by the Code de la nationalité belge (CNB), the Belgian Nationality Code. The Code was enacted as the Loi du 28 juin 1984 (published in the Moniteur belge of 12 July 1984) and has been amended on several occasions since.

The operative provisions for transmission of Belgian nationality to children are Articles 17 to 20 CNB:

• Article 17 governs the automatic transmission of Belgian nationality to a minor child (under 18) when the parent acquires Belgian nationality, provided the child is residing with that parent at the time of acquisition.
• Article 18 covers the retroactive incorporation of that nationality.
• Articles 19 and 20 govern declaration-based transmission, used where automatic transmission does not apply — for example, where a declaration must be made by the parent during the child's minority.

Belgian descent transmission operates on the principle of jus sanguinis (descent through a Belgian parent), with the underlying transmission rule grounded in Article 8 CNB. Where a declaration is required, it is made to the civil registrar (Officier de l'état civil / Ambtenaar van de Burgerlijke Stand) for a resident of Belgium, or through a Belgian consulate for an applicant abroad.

Subsequent amendments

The CNB has been amended over time, notably by:

• the Loi du 4 décembre 2012, which established the present integration-based naturalisation regime, including a five-year continuous integration pathway that replaced the earlier declaration regime; and
• the Loi du 18 juin 2024, which codified into Belgian law the EU proportionality framework for loss of nationality developed by the Court of Justice of the European Union in Tjebbes (C-221/17) and Rottmann (C-135/08).

Other framework articles of the Code relevant to acquisition and procedure include Articles 8, 9, 10, 11, 11bis, 12, 12bis (1° to 5°), 13, 22, 23, 23/1 and 24. In the context of international adoption, the Hague Adoption Convention of 1993 is implemented in Belgium by the Loi du 24 avril 2003, with an administrative framework set out in the Arrêté ministériel of 1 March 2019.

Uniform federal application

Descent-based transmission is federal and uniform: the CNB applies in the same way across the French-, Dutch- and German-language regions, and there is no regional variation in the rules of transmission. The competent official for registering the relevant declaration is the civil registrar at the municipality of birth registration. The regional integration frameworks (Flemish inburgering, Walloon parcours d'intégration, Brussels primo-arrivants, and the German-speaking Community Dekret) operate under the competency allocation reflected in Article 12bis.

Supporting jurisprudence

The jus sanguinis framework has been reinforced by the Belgian courts. The Cour de cassation, in its judgment of 8 October 2020, reaffirmed sex-equality in jus sanguinis transmission, including for pre-1985 retroactive applications. The Cour constitutionnelle has further shaped Belgian nationality law through its rulings in cases 122/2013, 73/2014 and 198/2014.