Règle correspondante
Belgium
Practice relating to Rule 66. Non-Hostile Contacts between the Parties to the Conflict
Section A. General
Belgium’s Field Regulations (1964) provides: “It is prohibited to enter in contact with the enemy, except with deserters, the wounded and parlementaires.” 
Belgium, Règlement sur le Service en Campagne, Règlement IF 47, Ministère de la Défense Nationale, Etat-Major Général, Force Terrestre, Direction Supérieure de la Tactique, Direction Générale du Planning, Entraînement et Organisation, 1964, § 21.
Belgium’s Law of War Manual (1983) states:
Relations between military commanders in the field of operations are necessary … for military or humanitarian purposes …
It is indispensable that, from both sides, these relations [intercourse between belligerents] be marked by the most scrupulous good faith and that no party takes any advantage from these relations that the other party does not intend to concede. 
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. 40.