Related Rule
Greece
Practice Relating to Rule 51. Public and Private Property in Occupied Territory
In its judgment in the Prefecture of Voiotia case in 1997, Greece’s Court of First Instance of Leivadia stated:
[T]he occupant is obliged to respect, during the administration of the occupied land, the legislation of the latter (article 43 of the fourth Hague Convention 1907) as well as international law, including the provisions of the Regulation of Laws and Customs of War on Land, annexed to the fourth Hague Convention (19th October 1907) … especially the provision of article 46, according to which “… private property … must be respected”. This rule is generally accepted as constituting peremptory international customary law (jus cogens). 
Greece, Court of First Instance of Leivadia, Prefecture of Voiotia case, Judgment of 30 October 1997.
In its judgment in the Margellos case in 1999, Greece’s Court of Appeal of Athens stated:
The generally accepted rules of international law that govern the obligations of the occupying power in relation to the administration of the occupied land are included in the Regulation of Laws and Customs of War on Land, annexed to the fourth Hague Convention (19th October 1907). Although not ratified by Greece, this Regulation constitutes international customary law (see the judgement of the International Military Tribunal for Germany) … The deliberate arson and damage to property, in violation of international ius cogens rules, committed by the German occupation army against Greek civilians, are of a iure gestionis nature, because these acts do not form part of the powers that can be exercised by an occupation army. The above-mentioned rule is of a ius cogens nature and its violation deprives the foreign state of the right to claim immunity. 
Greece, Court of Appeal of Athens, Margellos case, Judgment, 1999.