Related Rule
France
Practice Relating to Rule 10. Civilian Objects’ Loss of Protection from Attack
Section B. Situations of doubt as to the character of an object
France’s LOAC Manual (2001) states: “In case of doubt, an object usually affected to a civilian use must be considered as civilian and shall not be attacked.” 
France, Manuel de droit des conflits armés, Ministère de la Défense, Direction des Affaires Juridiques, Sous-Direction du droit international humanitaire et du droit européen, Bureau du droit des conflits armés, 2001, p. 90.