Règle correspondante
Switzerland
Practice Relating to Rule 17. Choice of Means and Methods of Warfare
Switzerland’s Regulation on Legal Bases for Conduct during an Engagement (2005) states:
12.5 Precautionary measures
165 The following precautionary measures must be taken into consideration when making decisions, when issuing orders and in particular when conducting military operations.
166 Anyone who attacks:
2 must take all required precautions when choosing the means and methods of attack with a view to limiting maximally loss, injury and damage among the civilian population and its property. 
Switzerland, Bases légales du comportement à l’engagement (BCE), Règlement 51.007/IVf, Swiss Army, issued based on Article 10 of the Ordinance for the Organization of the Federal Department for Defence, Civil Protection and Sports of 7 March 2003, entry into force on 1 July 2005, §§ 165–166(2). The German language version notes in § 166(2): “must take all feasible precautions ... with a view to minimizing loss, injury and damage among the civilian population and its property [“muss ... alle praktisch möglichen Vorsichtsmassnahmen treffen, um Verluste, Verwundete und Schädigungen an der Zivilbevölkerung und deren Eigentum auf ein Mindestmass zu beschränken”]”.
[emphasis in original]
In 2005, Switzerland withdrew its reservations to Articles 57 and 58 of the 1977 Additional Protocol I. 
Switzerland, Withdrawal of reservations to the 1977 Additional Protocol I, 17 June 2005.