Règle correspondante
Practice Relating to Rule 147. Reprisals against Protected Objects
Section C. Cultural property
Indonesia’s Air Force Manual (1990) provides that a “reprisal is absolutely prohibited against protected persons and objects”. 
Indonesia, The Basics of International Humanitarian Law in Air Warfare, Indonesian Air Force, 1990, § 15(c).
According to the Report on the Practice of Indonesia:
The meaning of … the protected objects is not only referring to the Geneva Conventions … but also referring to the customary sources, such as the moral values which are generally recognized and exist among the international community, and other Conventions such as the Convention for the protection of the cultural property which [has] already [been] ratified by Indonesia. 
Report on the Practice of Indonesia, 1997, Chapter 2.9.