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. 48.
Art. 48. If, in the territory occupied, the occupant collects the taxes, dues, and tolls imposed for the benefit of the State, he shall do so, as far as is possible, in accordance with the rules of assessment and incidence in force, and shall in consequence be bound to defray the expenses of the administration of the occupied territory to the same extent as the legitimate Government was so bound.