Annex to the Convention: Regulations respecting the laws and customs of war on land - Section III : Military authority over the territory of the hostile state - Regulations: Art. 55.
Art. 55. The occupying State shall be regarded only as administrator and usufructuary of public buildings, real estate, forests, and agricultural estates belonging to the hostile State, and situated in the occupied country. It must safeguard the capital of these properties, and administer them in accordance with the rules of usufruct.