Related Rule
Germany
Practice Relating to Rule 47. Attacks against Persons Hors de Combat
Germany’s Law Introducing the International Crimes Code (2002) punishes anyone who, in connection with an international or a non-international armed conflict, “wounds a member of the opposing armed forces or a combatant of the adverse party after the latter … is … placed hors de combat”. 
Germany, Law Introducing the International Crimes Code, 2002, Article 1(8)(2).
According to the Report on the Practice of Germany, the right to be given quarter is for the benefit of every person. 
Report on the Practice of Germany, 1997, Answers to additional questions on Chapter 2.1.
Germany’s Soldiers’ Manual (1991) contains the rule: “Never fight against an opponent who has laid down arms or has surrendered.” 
Germany, Taschenkarte, Humanitäres Völkerrecht in bewaffneten Konflikten – Grundsätze, Bearbeitet nach ZDv 15/2, Humanitäres Völkerrecht in bewaffneten Konflikten – Handbuch, Zentrum Innere Führung, June 1991, § 604, picture 601, pp. 33–34.
Germany’s Military Manual (1992) states: “An enemy who, having laid down his arms, or having no longer means of defence, surrenders or is otherwise unable to fight or to defend himself shall no longer be made the object of 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 KonfliktenHandbuch, August 1992, § 705.
The manual further states: “Grave breaches of international humanitarian law are in particular: … launching attacks against defenceless persons.” 
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, § 1209.
Germany’s Soldiers’ Manual (2006) states:
Only that violence may be used which is necessary to strike down the adversary. The defenceless or surrendering adversary may no longer be fought.
The wounded, sick and shipwrecked shall be respected and protected in all circumstances. Any violence to their lives or persons is prohibited. 
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, pp. 3 and 5.
The manual further recognizes the white flag as the flag of parlementaires and the flag of surrendering combatants. 
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. 6.
Germany’s Law Introducing the International Crimes Code (2002) punishes anyone who, in connection with an international or non-international armed conflict, “wounds a member of the opposing armed forces or a combatant of the adverse party after the latter has surrendered unconditionally”. 
Germany, Law Introducing the International Crimes Code, 2002, Article 1(8)(2).
In its judgment in the Stenger and Cruisus case after the First World War, Germany’s Leipzig Court specified that an order to shoot down men who were abusing the privileges of captured or wounded men
would not have been contrary to international principles, for the protection afforded by the regulations for land warfare does not extend to such wounded who take up arms again and renew the fight. Such men have by doing so forfeited the claim for mercy granted to them by the laws of warfare. 
Germany, Leipzig Court, Stenger and Cruisus case, Judgment, 1921.
In the Llandovery Castle case in 1921, Germany’s Reichsgericht found the accused, two crew officers, guilty of having fired upon enemies in lifeboats in violation of the laws and customs of war after their hospital ship had been sunk. The prosecutor emphasized that “in war at sea the killing of ship-wrecked persons who have taken refuge in lifeboats is forbidden”. The Court rejected the accused’s defence of superior orders on the ground that the rule prohibiting firing on lifeboats was “simple and universally known”. 
Germany, Reichsgericht, Llandovery Castle case, Judgment, 16 July 1921.
Upon ratification of the 1977 Additional Protocol I, Germany stated that it understood the word “feasible” to mean “that which is practicable or practically possible, taking into account all circumstances ruling at the time, including humanitarian and military considerations”. 
Germany, Declarations made upon ratification of the 1977 Additional Protocol I, 14 February 1991, § 2.