Related Rule
Belgium
Practice Relating to Rule 8. Definition of Military Objectives
Belgium’s Law of War Manual (1983) states:
Considered as military objectives are:
1) Persons: combatants
2) Objects: a) objects which by their nature, location, purpose or use make an effective contribution to military action
and
b) whose total or partial destruction, capture or neutralization, in the circumstances ruling at the time, offers a definite military advantage
3) Places: every defended position. This does not necessarily mean that it must be reinforced: it is sufficient that enemy troops go through it, or that it is protected by mine fields, or that its access is closed by artillery fire. 
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, p. 27.
Belgium’s Regulations on the Tactical Use of Large Units (1994) states: “An objective is the final goal of an action. It is defined as either an area of land of tactical importance or as enemy elements that have to be destroyed or neutralized.” 
Belgium, L’Emploi Tactique des Grandes Unités, Règlement G 119, Ministère de la Défense Nationale, Etat-Major Général, Force Terrestre, Sections Operations et Entraînement, 1994 (édition provisoire), § 210.
Belgium’s Law of War Manual (1983) considers combatants to be military objectives. 
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, p. 27.
Belgium’s Teaching Manual for Soldiers considers that “all objects occupied or used by enemy military forces (positions, barracks, depots, etc.)” are military objectives. 
Belgium, Droit de la Guerre, Dossier d’Instruction pour Soldat, à l’attention des officiers instructeurs, JS3, Etat-Major Général, Forces Armées belges, undated, p. 20.
Belgium’s Law of War Manual (1983) considers that “the army, its positions, provision of its supplies, its stores, workshops, arsenals, depots, defence works, … war buildings, etc.” are military objectives. 
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, p. 26.
Belgium’s Law of War Manual (1983) considers that military vehicles and aircraft are military objectives. 
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, p. 26.
Belgium’s Law of War Manual (1983) states:
The purpose of combat between belligerents is to weaken and eliminate the power of resistance of the enemy.
This resistance is provided in the first place by the armed forces of a Party to the conflict. As a result, acts of violence are in the first place directed against the military potential of the adversary (the army, its positions, provision of its supplies, its stores, workshops, arsenals, depots, defence works, vehicles, aircraft, war buildings, etc.).
But this resistance also depends on the economic power of the adversary (its war industry, its production capacity, its sources of supply, etc.); in short, its economic potential. The breaking up of this economic potential has of course a direct influence on the armed forces’ capacity to resist, so that this economic potential also becomes a war objective. 
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, p. 26.
Belgium’s Regulations on Armoured Infantry Squads (1972) defines the objective of a mission as “a vital area of land to be conquered or defended”. 
Belgium, Le Peloton d’Infanterie Blindée, Règlement G 176, Ministère de la Défense Nationale, Etat-Major Général, Force Terrestre, Direction de l’Infanterie, des Paras-Commandos et de la Police Militaire, 1972, p. 3.
Belgium’s Regulations on Tank Squadrons (1982) states that the objective of a tank squadron in attack is “an area of land whose capture requires the enemy’s destruction or withdrawal”. 
Belgium, L’Escadron de Chars, Règlement G 287, Ministère de la Défense Nationale, Etat-Major Général, Force Terrestre, Ecole des Troupes Blindées, 1982, § 537(b)(2); see also §§ 536(b)(2) and 539(b)(2).
Belgium’s Regulations on the Tactical Use of Large Units (1994) states: “An objective is the final goal of an action. It is defined as either an area of land of tactical importance or as enemy elements that have to be destroyed or neutralized.” 
Belgium, L’Emploi Tactique des Grandes Unités, Règlement G 119, Ministère de la Défense Nationale, Etat-Major Général, Force Terrestre, Sections Operations et Entraînement, 1994 (édition provisoire), § 210.
In an explanatory memorandum submitted to the Belgian Parliament in 1985 in the context of the ratification procedure of the 1977 Additional Protocols, the Belgian Government stated:
The notion of “military objective” must be understood as meaning that a specific zone, as such, which by its location or other criteria enumerated in Article 52 makes an effective contribution to enemy military action, can be considered a military objective. 
Belgium, House of Representatives, Explanatory memorandum on a draft bill for the approval of the Additional Protocols, 1984–1985 Session, Doc. 1096-1, 9 January 1985, p. 10.
In an explanatory memorandum submitted to the Belgian Parliament in 1985 in the context of the ratification procedure of the 1977 Additional Protocols, the Belgian Government stated that “each person, even a civilian, who is located inside a military objective, is exposed to the consequences of the risks that objective runs”. 
Belgium, House of Representatives, Explanatory memorandum on a draft bill for the approval of the Additional Protocols, 1984–1985 Session, Doc. 1096-1, 9 January 1985, p. 10.