Règle correspondante
Practice Relating to Rule 140. The Principle of Reciprocity
At the CDDH, Mexico stated: “The mandatory nature of humanitarian law does not depend on the observance of its rules by the adverse Party, but stems from the inherently wrongful nature of the act prohibited by international humanitarian law.” 
Mexico, Statement at the CDDH, Official Records, Vol. IX, CDDH/I/SR.73, 16 May 1977, pp. 449–450.