Related Rule
Practice Relating to Rule 71. Weapons That Are by Nature Indiscriminate
Switzerland’s Basic Military Manual (1987), with respect to nuclear weapons, refers to Article 51 of the 1977 Additional Protocol I and states: “It is prohibited to use weapons the effects of which can harm civilian or military objectives without discrimination.” 
Switzerland, Lois et coutumes de la guerre (Extrait et commentaire), Règlement 51.7/II f, Armée Suisse, 1987, Article 24.
In 1974, during discussions in the Ad Hoc Committee on Conventional Weapons established by the CDDH, the representative of Switzerland stated:
24. He entirely agreed with the Swedish representative. Two basic principles provided the starting point for the Committee’s discussions: the prohibition of arms which caused unnecessary sufferings, and the distinction between the civilian population and armed forces. Those principles belonged to customary law. They were already in force, and were to be found in the Declaration of St. Petersburg and the Hague Conventions. The ICRC had taken over those principles in articles 33 and 43(3) of draft Protocol I. The proposals put forward by a number of delegations … were merely executing rules: they were not aimed at creating new law, but at clarifying and illustrating the rules already in force.
25. … The problems of banning or restricting the use of certain categories of weapons [introduced by draft Article 33 of the 1977 Additional Protocol I submitted to the CDDH by the ICRC] … was a question of a codification of existing law rather than the creation of new legal norms …
26. … The weapons in question – incendiary or fragmentation weapons, high-velocity projectiles, fléchettes, etc. – were small weapons and could have no decisive impact on the outcome of a conflict; but there was a grave disparity between the suffering they caused and the military advantage they might confer. Even if they were used in defiance of a ban, the advantage of surprise thus gained would be ephemeral. 
Switzerland, Statement at the CDDH, Official Records, Vol. XVI, CDDH/IV/SR.1, 13 March 1974, pp. 12–13, §§ 24–26.
Switzerland’s ABC of International Humanitarian Law (2009) states:
… The principle of distinction imposes limits on means and methods of warfare: any Weapon or strategy that cannot be directed exclusively at a specific military objective is prohibited.
International humanitarian law imposes limitations, in some cases a total ban, on the use of weapons whose impact goes beyond the permissible purpose of weakening the enemy. Weapons are prohibited on the basis of three fundamental criteria: if their use inevitably leads to death; if they cause disproportionate injury or Unnecessary suffering; if they strike indiscriminately. On the basis of these three criteria a number of specific weapons have been explicitly prohibited by international conventions, including Anti-personnel mines, Cluster munitions, blinding laser weapons, Dumdum bullets as well as Biological and Chemical weapons. Some of these bans are part of Customary international law. 
Switzerland, Federal Department of Foreign Affairs, ABC of International Humanitarian Law, 2009, pp. 17 and 40.
In 2010, in its Report on Foreign Policy, Switzerland’s Federal Council stated that Switzerland “aims … to prohibit weapons producing excessively traumatic effects or striking without discrimination”. 
Switzerland, Federal Council, Report on Foreign Policy 2010, 10 December 2010, Section 4.5.2, p. 1137.
In 2012, in a speech on the occasion of Public International Law Day, the head of Switzerland’s Federal Department of Foreign Affairs stated that international humanitarian law “also prohibits the use of weapons that have indiscriminate effects, such as chemical weapons or arms with cluster munitions”. 
Switzerland, Speech by the head of the Federal Department of Foreign Affairs on the occasion of Public International Law Day, 19 October 2012.
In 2013, in a statement at the Meeting of the High Contracting Parties to the Convention on Certain Conventional Weapons, the permanent representative of Switzerland stated:
The community of States cannot remain indifferent to the human suffering caused by armed conflicts. It was in direct response to this fundamental concern that the CCW [1980 Convention on Certain Conventional Weapons] and its protocols were adopted, with a view to prohibiting or limiting the use of certain specific types of weapon known to inflict superfluous injury or unnecessary suffering, or to strike indiscriminately. 
Switzerland, Statement by the permanent representative of Switzerland at the Meeting of the High Contracting Parties to the Convention on Certain Conventional Weapons, 14 November 2013.