Règle correspondante
Practice Relating to Rule 30. Persons and Objects Displaying the Distinctive Emblem
Germany’s Military Manual (1992) provides:
The distinctive emblem of medical and religious personnel as well as that of medical establishments (including hospital ships), medical transports, medical material and hospital zones is the red cross on a white ground. Countries which wish to use the red crescent in place of the red cross shall be free to do so. The two distinctive emblems have no religious significance; they must be equally respected in all places, and at all times. 
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 KonfliktenHandbuch, August 1992, § 637.
Germany’s Soldiers’ Manual (2006) states: “Combat operations may not be directed against persons or objects that are under the protection of the red cross or other distinctive emblems.” 
Germany, Druckschrift Einsatz Nr. 03, Humanitäres Völkerrecht in bewaffneten Konflikten – Grundsätze, Erarbeitet nach ZDv 15/2, Humanitäres Völkerrecht in bewaffneten Konflikten – Handbuch, DSK SF009320187, Bundesministerium der Verteidigung, R II 3, August 2006, p. 3.
Germany’s Law Introducing the International Crimes Code (2002) provides:
Anyone who, in connection with an international or non-international armed conflict, … carries out an attack against personnel, buildings, material or medical units and transport designated with the distinctive emblems of the Geneva Conventions … in conformity with international humanitarian law, shall be liable to imprisonment for not less than three years. In less serious cases, particularly where the attack is not carried out with military means, the period of imprisonment shall be for not less than one year. 
Germany, Law Introducing the International Crimes Code, 2002, Article 1, § 11(1)(2).