Related Rule
Belgium
Practice Relating to Rule 130. Transfer of Own Civilian Population into Occupied Territory
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 … :
31. the transfer, directly or indirectly, by the Occupying Power (in the case of international armed conflicts) or authority (in the case of non-international armed conflicts) of parts of its own civilian population into the territory it occupies. 
Belgium, Penal Code, 1867, as amended on 5 August 2003, Chapter III, Title I bis, Article 136 quater, § 1(31).
Under Belgium’s Law concerning the Repression of Grave Breaches of the Geneva Conventions and their Additional Protocols (1993), as amended in 1999, “the transfer by the occupying power of parts of its own civilian population into the territory it occupies, in the case of an international armed conflict, or of the occupying authority, in the case of a non-international armed conflict,” is criminalized as a grave breach. 
Belgium, Law concerning the Repression of Grave Breaches of the Geneva Conventions and their Additional Protocols, 1993, as amended in 1999, Article 1(3)(17).
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 … :
17. the transfer, directly or indirectly, by the Occupying Power (in the case of international armed conflicts) or authority (in the case of non-international armed conflicts) of parts of its own civilian population into the territory it occupies. 
Belgium, Law relating to the Repression of Grave Breaches of International Humanitarian Law, 1993, as amended on 23 April 2003, Article 1 ter, § 1(17).