Related Rule
Switzerland
Practice Relating to Rule 47. Attacks against Persons Hors de Combat
Section A. General
Under Switzerland’s Basic Military Manual (1987), “attacks directed against a person, in the knowledge that this person is hors de combat,” are grave breaches of the 1977 Additional Protocol I. 
Switzerland, Lois et coutumes de la guerre (Extrait et commentaire), Règlement 51.7/II f, Armée Suisse, 1987, Article 193(1)(e).
Switzerland’s Aide-Memoire on the Ten Basic Rules of the Law of Armed Conflcit (2005) states:
Rule 2
I spare persons that surrender or are hors de combat. I can therefore also expect the enemy to treat me humanely.
Rule 5
I treat people that fall into my hands humanely. I disarm them and hand them over to my superior. They have to be protected from any kind of attack. … At the same time, I always take my own safety and that of my comrades into account. 
Switzerland, The Ten Basic Rules of the Law of Armed Conflict, Aide-memoire 51.007/IIIe, Swiss Army, issued based on Article 10 of the Ordinance for Organisation of the Federal Department for Defence, Civil Protection and Sports dated 7 March 2003, entry into force on 1 July 2005, Rules 2 and 5.
Switzerland’s Regulation on Legal Bases for Conduct during an Engagement (2005) states:
12.1 The principle of distinction
159 Hostilities may exclusively be directed against combatants and military targets.
3 Protected persons are persons who are not or no longer taking part in combat or enjoy specially protected status, such as medical and religious personnel, civil protection or cultural property protection personnel, as well as wounded persons and prisoners of war.
13 Protected persons
13.1 Behaviour with regard to the wounded, sick and shipwrecked and medical and religious personnel
173 Wounded, sick and shipwrecked persons become protected persons as soon as they have laid down their arms or are hors de combat. They must not be attacked.
13.2 Behaviour with regard to combatants and prisoners
182 Persons who clearly indicate their willingness to surrender may not be attacked. As soon as circumstances permit, they must be searched, disarmed and evacuated from the danger zone. This must be done while constantly ensuring one’s own safety at all times (surveying the battlefield, cover, protection against fire).
183 As long as they do not defend themselves, pilots and crew members who parachute from an enemy aircraft in distress to save their own lives may neither be attacked from the air nor from the ground. Once landed, they are treated as prisoners of war. If they do not surrender or resist capture they are considered combatants and may be rendered hors de combat.
15 Methods of warfare
225 Indiscriminate attacks, i.e. attacks which cannot distinguish between protected persons/objects and military objectives, as well as attacks directed against protected persons/objects or acts of revenge are prohibited in any place and at any time.
17 Sanctions for violations of the international law of armed conflict
237 The following in particular are criminal offences: … harmful acts against internationally protected persons and objects[.] 
Switzerland, Bases légales du comportement à l’engagement (BCE), Règlement 51.007/IVf, Swiss Army, issued based on Article 10 of the Ordinance on the Organization of the Federal Department for Defence, Civil Protection and Sports of 7 March 2003, entry into force on 1 July 2005, §§ 159(3), 173, 182–183, 225 and 237. The German language version notes in the first sentence of § 173: “… as soon as they have laid down their arms or are otherwise [“sonstwie”] hors de combat.” Heading 13.2 reads in the German language version: “Behaviour with regard to surrendering [“sich ergebenden”] combatants and prisoners”.
Switzerland’s Military Criminal Code (1927), taking into account amendments entered into force up to 2011, states in a chapter entitled “War crimes”:
Art. 110
Articles 112–114 apply in the context of international armed conflicts, including in situations of occupation, and, if the nature of the offence does not exclude it, in the context of non-international armed conflicts.
Art. 112c
1 The penalty shall be a custodial sentence of not less than three years for any person who, in the context of an armed conflict:
d. kills or wounds an enemy combatant … who is hors de combat. 
Switzerland, Military Criminal Code, 1927, taking into account amendments entered into force up to 2011, Articles 110 and Article 112c (1)(d).
Switzerland’s Penal Code (1937), taking into account amendments entered into force up to 2011, states under the title “War crimes”:
Art. 264b
Articles 264d–264j apply in the context of international armed conflicts, including in situations of occupation, and, if the nature of the offence does not exclude it, in the context of non-international armed conflicts.
Art. 264g
1 The penalty shall be a custodial sentence of not less than three years for any person who, in the context of an armed conflict:
d. kills or wounds an enemy combatant … who is hors de combat. 
Switzerland, Penal Code, 1937, taking into account amendments entered into force up to 2011, Articles 264b and 264g (1)(d).
Switzerland’s ABC of International Humanitarian Law (2009) states: “Even in war not everything is allowed. Various means and methods are prohibited, including … denying protection to persons who are hors de combat.” 
Switzerland, Federal Department of Foreign Affairs, ABC of International Humanitarian Law, 2009, p. 29.