Chapter II: Enemy civilians in the territory of a belligerent#Section I: General Provisions - Art. 4.
Detention of Civilians.
Article 4.- Only civilians falling within the following categories may be held:
a) Those who are eligible for immediate mobilisation or mobilisation within a year, under the laws of their country of origin or of the country of residence;
b) those whose departure may reasonably be opposed on grounds involving the security of the Detaining Power.
In either case, appeal to the Protecting Power shall always be admitted. This Power shall have the right to demand that an inquiry be opened and the result communicated to it within three months of its request.