Switzerland
Practice Relating to Rule 33. Personnel and Objects Involved in a Peacekeeping Mission
Switzerland’s Aide-Memoire on the Ten Basic Rules of the Law of Armed Conflict (2005) states: “I spare and respect personnel and installations as well as equipment and means of transport of … the United Nations without discrimination unless they open fire on my comrades or me.”
The Aide-Memoire further states with regards to the UN:
Correct behaviour
Personnel, installations, material and means of transport of the UN as well as bearers of distinctive signs or objects marked with distinctive signs must be respected and spared.
Prohibited is/are …
Damaging action against personnel, installations and material, as long as these are not involved in combat[.]
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. 112
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 directs an attack against:
…
b. … personnel, installations, material or vehicles involved in a … peacekeeping mission in accordance with the Charter of the United Nations of 26 June 1945, as long as they are protected by international humanitarian law.

[footnote in original omitted]
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. 264d
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 directs an attack against:
…
b. … personnel, installations, material or vehicles involved in a … peacekeeping mission in accordance with the Charter of the United Nations of 26 June 1945, as long as they are protected by international humanitarian law.

[footnote in original omitted]