Related Rule
Belgium
Practice Relating to Rule 96. Hostage-Taking
Belgium’s Law of War Manual (1983) prohibits hostage-taking and adds that it constitutes a grave breach of the 1949 Geneva Conventions. 
Belgium, Droit Pénal et Disciplinaire Militaire et Droit de la Guerre, Deuxième Partie, Droit de la Guerre, Ecole Royale Militaire, par J. Maes, Chargé de cours, Avocat-général près la Cour Militaire, D/1983/1187/029, 1983, pp. 50 and 55.
Belgium’s Teaching Manual for Soldiers explains that the prohibition on taking hostages is a necessary corollary of the obligation to respect the civilian population. 
Belgium, Droit de la Guerre, Dossier d’Instruction pour Soldat, à l’attention des officiers instructeurs, JS3, Etat-Major Général, Forces Armées belges, undated, pp. 10, 14 and 41 and slide 1/7.
Belgium’s Penal Code (1867), as amended in 2003, provides:
War crimes envisaged in the 1949 [Geneva] Conventions … and in the [1977 Additional Protocols I and II] … , as well as in Article 8(2)(f) of the [1998 ICC Statute], and listed below, … constitute crimes under international law and shall be punished in accordance with the provisions of the present title … :
11. hostage-taking. 
Belgium, Penal Code, 1867, as amended on 5 August 2003, Chapter III, Title I bis, Article 136 quater, § 1(11).
The Penal Code further states:
In the case of an armed conflict as defined in … Article 3 common [to the (1949) Geneva Conventions], the grave breaches of [common] Article 3, … listed below, shall constitute crimes under international law and shall be punished in accordance with the provisions of the present title, when such breaches endanger, by act or omission, persons protected by these Conventions, without prejudice to criminal provisions applicable to breaches committed out of negligence:
3. hostage-taking. 
Belgium, Penal Code, 1867, as amended on 5 August 2003, Chapter III, Title I bis, Article 136 quater, § 2(3).
Belgium’s Law concerning the Repression of Grave Breaches of the Geneva Conventions and their Additional Protocols (1993), as amended in 1999, provides that hostage-taking constitutes a crime under international law. 
Belgium, Law concerning the Repression of Grave Breaches of the Geneva Conventions and their Additional Protocols, 1993, as amended in 1999, Article 1(3)(7).
Belgium’s Law relating to the Repression of Grave Breaches of International Humanitarian Law (1993), as amended in 2003, provides:
War crimes envisaged in the 1949 [Geneva] Conventions … and in the [1977 Additional Protocols I and II] … , as well as in Article 8(2)(f) of the [1998 ICC Statute], and listed below, … constitute crimes under international law and shall be punished in accordance with the provisions of the present title … :
7. hostage-taking. 
Belgium, Law relating to the Repression of Grave Breaches of International Humanitarian Law, 1993, as amended on 23 April 2003, Article 1 ter, § 1(7).
The Law further states:
In the case of an armed conflict as defined in … Article 3 common [to the (1949) Geneva Conventions], the grave breaches of [common] Article 3, … listed below, shall constitute crimes under international law and shall be punished in accordance with the provisions of the present title, when such breaches endanger, by act or omission, persons protected by these Conventions, without prejudice to criminal provisions applicable to breaches committed out of negligence:
3. hostage-taking. 
Belgium, Law relating to the Repression of Grave Breaches of International Humanitarian Law, 1993, as amended on 23 April 2003, Article 1 ter, § 2(3).