Marriage-based pathway via Article 12bis §1 4° (extended view)

This is Belgium's marriage-based naturalisation pathway under Article 12bis §1 4° of the Code de la nationalité belge (CNB). It allows a foreign national married to a Belgian citizen to acquire Belgian nationality by declaration, provided the applicant has lived in Belgium for five years of legal residence, has cohabited with the Belgian-national spouse for at least three years, can show evidence of social and economic integration, and demonstrates language proficiency (A2 level in one of the national languages).

Same-sex couples are treated on an equal footing: since the Loi du 13 février 2003 opened marriage to same-sex partners, a same-sex Belgian-national spouse triggers the same Article 12bis §1 4° pathway. Under a broader (extended) reading of the provision, the cohabitation requirement can also be satisfied through registered partnership — legal cohabitation (cohabitation légale / wettelijke samenwoning).

Belgian nationality is an exclusive federal competence under Article 8 of the Constitution and is governed by the Code de la nationalité belge (Loi du 28 juin 1984, M.B. 12 juillet 1984), as amended — notably by the Loi du 4 décembre 2012, which introduced the current integration-based declaration regime, and the Loi du 18 juin 2024. Belgium's trilingual federal structure means the procedure is handled within the relevant linguistic community (French, Dutch, or German).

The declaration is filed with the Officier de l'état civil at the applicant's commune. The Procureur du Roi (Parquet) may issue an opinion or lodge an opposition within the statutory window, after which a decision is taken and, if positive, recorded in the National Register. A negative decision may be challenged before the administrative chamber of the Conseil d'État within the applicable deadline.

Eligibility framework: thresholds calibrated per Code de la nationalité belge (CNB) — Loi du 28 juin 1984 as amended by Loi du 4 décembre 2012 — CNN regime (5-year continuous integration pathway; replaced declaration regime). Language pillar: Dutch OR French OR German per linguistic community (Loi du 18 juillet 1966). Standard floor: 5 years continuous residence (one of three integration pathways under 2012 CNN regime). Region-specific integration: Region-specific integration: Flemish inburgering (VL) / Walloon parcours d'intégration (W) / Brussels primo-arrivants (BXL). EU-loss proportionality where relevant: CJEU Tjebbes C-221/17 + Rottmann C-135/08 — EU proportionality for nationality loss (codified BE 2024).

Standard documentation set for MAR pathway: ID + foreign passport, residence permit (where applicable), region-specific integration certificate (Flemish inburgering / Walloon parcours / Brussels primo-arrivants / DE-Community Dekret), language proficiency certificate (A2/B1 by sub-pathway), tax records (last 3 years), Procureur du Roi clearance. Filing fee EUR 150. See DOFI Vademecum 'Nationalité' 2025 for comprehensive checklists.

Route-specific documentation requirements: statutory anchor under Article 12bis §1 4° CNB; Article 12bis §1 3° marriage track: certificate of marriage to BE national + 5-year cohabitation evidence (registres population / Rijksregister), residence permit chain, A2 language certificate, Procureur du Roi advisory opinion (60-day window). Cohabitation strictly enforced — separation defeats the track. Federal Mediator complaint route available (~150 nationality complaints/year); DOFI Vademecum 'Nationalité' provides comprehensive sub-pathway checklists. Filing fee EUR 150 per declaration (Loi 4 décembre 2012 + Royal Decree fee schedule).

Timeline: 4-12 months. Fee: EUR 150. Documentation requirements: 5y legal residence proof + 3y cohabitation evidence (joint address, shared finances, social-security records).

Procedural timeline + costs: declaration filed before the Officier de l'état civil (commune) + Parquet (4-month opposition window) + Tribunal de la famille. 4-month opposition window from the Parquet (Procureur du Roi). Decision communicated by registered post; absence of opposition = positive acquisition. Standard administrative fee (droit d'enregistrement) per 2024 Code; final inscription in registres de la nationalité. Anchor: Code de la nationalité belge (CNB) 1984 (Loi du 28 juin 1984) as amended by Loi 4 décembre 2012 (5-year continuous integration regime; replaced 'declaration' regime).

Procedural timeline + costs: declaration filed before the Officier de l'état civil (commune) + Parquet (Procureur du Roi — 4-month opposition window) + Tribunal de la famille. 4-month opposition window from the Parquet (Procureur du Roi). Decision communicated by registered post; absence of opposition = positive acquisition. Standard administrative fee (droit d'enregistrement) per 2024 Code; final inscription in registres de la nationalité. Anchor: Code de la nationalité belge (CNB) — Loi du 28 juin 1984 as amended by Loi du 4 décembre 2012 — CNN regime (5-year continuous integration pathway; replaced declaration regime).

Statutory anchor: Article 12bis §1 4° CNB; Loi 13 fév 2003 same-sex marriage. Article 12bis §1 4° CNB requires 5y joint legal residence + 3y cohabitation (or 5y marriage). Loi 13 fév 2003 same-sex marriage extends to civic marriage. CJEU Coman C-673/16 binds BE on same-sex spouse derivative residence. Federal-statutory (CNB applies uniformly across FR/NL/DE language regions); regional integration certificate framework (Flemish inburgering / Walloon parcours d'intégration / Brussels primo-arrivants / DE-Community Dekret) per Article 12bis competency-allocation.

Statutory anchor: Code de la nationalité belge (CNB) — Loi du 28 juin 1984 as amended by Loi du 4 décembre 2012 — CNN regime (5-year continuous integration pathway; replaced declaration regime) and Loi du 18 juin 2024 — Tjebbes codification (CJEU C-221/17 + Rottmann C-135/08 proportionality framework codified in BE law). Framework articles: Articles 8, 9, 10, 11, 11bis, 12, 12bis (1°-5°), 13, 22, 23, 23/1, 24 framework (CNB structure). EU-loss proportionality codified per CJEU Tjebbes C-221/17 + Rottmann C-135/08 — EU proportionality for nationality loss (codified BE 2024). Hague Adoption framework: Hague Adoption Convention 1993 — Loi du 24 avril 2003 BE-implementation; AM 1 mars 2019 administrative framework. Constitutional/jurisprudential anchors: C.C. 73/2014 + 122/2013 + 198/2014 — Cour Constitutionnelle nationality jurisprudence; Conseil d'État + Cour de Cassation apex review.

Appeal mechanism: Conseil d'Etat admin-chamber review (60-day deadline post-decision); naturalization refusal subject to procedural-deficiency review only - substantive parliamentary discretion (Article 13) NOT directly reviewable. Federal Mediator complaint route (~150 nationality complaints/year). Constitutional Court access for statutory challenges.

Sub-jurisdictional appeal architecture: Conseil d'État (Raad van State / Staatsrat) administrative chamber (60-day filing window post-notification); review limited to procedural-deficiency for parliamentary discretion (Art 13 CNB) but full substantive review for ministerial decisions (Art 12bis). Cour Constitutionnelle (Grondwettelijk Hof) for statutory challenges (Loi 6 jan 1989 framework). Cour de Cassation 1ère chambre for civil-law nationality determinations. CJEU Art 267 TFEU preliminary reference avenue preserved for Union-citizenship loss-effects under Tjebbes (C-221/17) + Rottmann (C-135/08) proportionality review codified by Loi 18 juin 2024.