Related Rule
Germany
Practice Relating to Rule 35. Hospital and Safety Zones and Neutralized Zones
Germany’s Military Manual (1992) provides:
Hospital and safety zones and localities shall be established on mutual agreement so as to protect wounded, sick and aged persons, children, expectant mothers and mothers of children under seven from any attack. 
Germany, Humanitarian Law in Armed Conflicts – Manual, DSK VV207320067, edited by The Federal Ministry of Defence of the Federal Republic of Germany, VR II 3, August 1992, English translation of ZDv 15/2, Humanitäres Völkerrecht in bewaffneten Konflikten – Handbuch, August 1992, § 512; see also § 463.
The manual further provides that grave breaches of IHL are in particular “launching attacks against … neutralized zones”. 
Germany, Humanitarian Law in Armed Conflicts – Manual, DSK VV207320067, edited by The Federal Ministry of Defence of the Federal Republic of Germany, VR II 3, August 1992, English translation of ZDv 15/2, Humanitäres Völkerrecht in bewaffneten Konflikten – Handbuch, August 1992, § 1209.