The purpose of establishing a Convention for the Protection of Civilian Persons in Time of War
Prisoners of war shall continue to have the benefit of such agreements as long as the Convention is applicable to them, except where express provisions to the contrary are contained in the aforesaid or in subsequent agreements, or where more favourable measures have been taken with regard to them by one or other of the Parties to the conflict.
The present Convention shall be applied with the cooperation and under the scrutiny of the Protecting Powers whose duty it is to safeguard the interests of the Parties to the conflict. For this purpose, the Protecting Powers may appoint, apart from their diplomatic or consular staff, delegates from amongst their own nationals or the nationals of other neutral Powers. The said delegates shall be subject to the approval of the Power with which they are to carry out their duties.
First Geneva Convention 1949: international law for the protection of the victims of armed conflicts
The Convention shall also apply to all cases of partial or total occupation of the territory of a High Contracting Party, even if the said occupation meets with no armed resistance.