Règle correspondante
Switzerland
Practice Relating to Rule 146. Reprisals against Protected Persons
Section E. Civilians in general
Switzerland’s Basic Military Manual (1987), in a part dealing with “Hostilities and their limits”, refers, inter alia, to Article 33 of the 1949 Geneva Convention IV and Articles 51, 54 and 55 of the 1977 Additional Protocol I and states: “Reprisals against the civilian population are prohibited.” 
Switzerland, Lois et coutumes de la guerre (Extrait et commentaire), Règlement 51.7/II f, Armée Suisse, 1987, Article 25(2).
In a part dealing with civilians and, more specifically, “civilian persons who are in the power of the troops at the moment of combat”, the manual refers to Article 33 of the 1949 Geneva Convention IV and Article 51 of the 1977 Additional Protocol I and states: “Measures of reprisal or attacks [carried out] as measures of reprisal are prohibited.” 
Switzerland, Lois et coutumes de la guerre (Extrait et commentaire), Règlement 51.7/II f, Armée Suisse, 1987, Article 149.
Switzerland’s ABC of International Humanitarian Law (2009) states:
Means and methods of warfare
Even in war not everything is allowed. Various means and methods are prohibited, including … Reprisals against the civilian population or against non-military objectives[.] 
Switzerland, Federal Department of Foreign Affairs, ABC of International Humanitarian Law, 2009, p. 29.