Related Rule
Canada
Practice Relating to Rule 39. Use of Cultural Property for Military Purposes
Canada’s LOAC Manual (1999) states that it is prohibited to use historic monuments, works of art or places of worship which constitute the cultural or spiritual heritage of peoples “in support of the military effort”. 
Canada, The Law of Armed Conflict at the Operational and Tactical Level, Office of the Judge Advocate General, 1999, p. 4-7, § 63(b).
The manual further provides that “use of a privileged building for improper purposes” constitutes a war crime. 
Canada, The Law of Armed Conflict at the Operational and Tactical Level, Office of the Judge Advocate General, 1999, p. 16-4, § 21(c).
The manual restates this prohibition with respect to non-international armed conflicts in particular. 
Canada, The Law of Armed Conflict at the Operational and Tactical Level, Office of the Judge Advocate General, 1999, p. 17-5, § 40.
Canada’s Code of Conduct (2001) states: “Cultural and religious property should … not be used for military purposes.” 
Canada, Code of Conduct for CF Personnel, Office of the Judge Advocate General, 4 June 2001, Rule 9, § 5.
Canada’s LOAC Manual (2001) states in its chapter on targeting:
1. The following actions are prohibited:
a. to commit any acts of hostility directed against the historic monuments, works of art or places of worship which constitute the cultural or spiritual heritage of peoples; or
b. to use such objects in support of the military effort.
2. Care must be taken to avoid locating military personnel and material in or near protected cultural objects and places of worship. 
Canada, The Law of Armed Conflict at the Operational and Tactical Levels, Office of the Judge Advocate General, 13 August 2001, § 443.1–2.
In its chapter on “War crimes, individual criminal liability and command responsibility”, the manual states that “use of a privileged building for improper purposes” constitutes a war crime. 
Canada, The Law of Armed Conflict at the Operational and Tactical Levels, Office of the Judge Advocate General, 13 August 2001, § 1609.3.c.
In its chapter on non-international armed conflicts, the manual states:
It is forbidden to commit any hostile acts directed against historic monuments, works of art or places of worship that constitute the cultural or spiritual heritage of peoples. It is also forbidden to use them in support of the military effort. 
Canada, The Law of Armed Conflict at the Operational and Tactical Levels, Office of the Judge Advocate General, 13 August 2001, § 1723.
Canada’s Code of Conduct (2005) states:
Cultural and religious property should not be targeted. It should also not be used for military purposes. If cultural or religious property is used for a military purpose, it loses its protection. Thus, care must be taken to avoid locating military personnel and material in or near these locations. If the opposing force is using a religious or cultural site for military purposes it becomes a legitimate target. 
Canada, Code of Conduct for CF Personnel, Office of the Judge Advocate General, 2005, Rule 9, § 5.
Upon ratification of the 1977 Additional Protocol I, Canada stated:
It is the understanding of the Government of Canada in relation to Article 53 that … the prohibitions contained in sub-paragraphs (a) and (b) of this Article can only be waived when military necessity imperatively requires such a waiver. 
Canada, Reservations and statements of understanding made upon ratification of the 1977 Additional Protocol I, 20 November 1990, § 9.