Annex to the Convention: Regulations respecting the laws and customs of war on land - Section I : On belligerents - Chapter II : Prisoners of war - Regulations: Art. 10.
Art. 10. Prisoners of war may be set at liberty on parole if the laws of their country allow, and, in such cases, they are bound, on their personal honour, scrupulously to fulfil, both towards their own Government and the Government by whom they were made prisoners, the engagements they have contracted.
In such cases their own Government is bound neither to require of nor accept from them any service incompatible with the parole given.