Related Rule
Practice Related to Rule 95. Forced Labour
Section B. Compelling persons to serve in the forces of a hostile power
Spain’s LOAC Manual (2007) states: “It is prohibited to compel the inhabitants of an occupied territory to enlist in the armed forces of the occupying power.” 
Spain, Orientaciones. El Derecho de los Conflictos Armados, Tomo 1, Publicación OR7–004, (Edición Segunda), Mando de Adiestramiento y Doctrina, Dirección de Doctrina, Orgánica y Materiales, 2 November 2007, § 2.7.c.(3).
(emphasis in original)
Spain’s Military Criminal Code (1985) punishes the compelling of prisoners of war and civilians to fight against their own forces. 
Spain, Military Criminal Code, 1985, Article 77(5)–(6).
Spain’s Penal Code (1995) provides for the punishment of anyone found guilty of “compelling a prisoner of war or a civilian person to serve, in whatever form, in the Armed Forces of the Adverse Party”. 
Spain, Penal Code, 1995, Article 611(3).