Соответствующая норма
Practice Relating to Rule 75. Riot Control Agents
Switzerland’s Regulation on Legal Bases for Conduct during an Engagement (2005) states:
16.1 Prohibited means of warfare
230 The following are also prohibited during combat in armed conflicts:
2 tear gas and other irritant gases. 
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, § 230(2).