Chapter II
Crimes
Section II
War crimes
Article 10
War crimes against persons
2. Anyone who, in the context of an international armed conflict:
(b) Compels prisoner of war or other protected person to serve in the forces of a hostile power;
shall be punished with a term of imprisonment of 10 to 25 years.
Compelling a prisoner of war to serve in the forces of a hostile power - IAC
Compelling a protected person to serve in the forces of a hostile power - IAC
EDIT.