Related Rule
Netherlands
Practice Relating to Rule 100. Fair Trial Guarantees
Section A. General
The Military Manual (1993) of the Netherlands prohibits punishments “without a previous judgment … through a fair trial”. 
Netherlands, Toepassing Humanitair Oorlogsrecht, Voorschift No. 27-412/1, Koninklijke Landmacht, Ministerie van Defensie, 1993, p. VII-2.
The manual further states that “wilfully depriving a protected person of the rights of a fair and regular trial” is a grave breach of the 1949 Geneva Conventions and their 1977 Additional Protocols. 
Netherlands, Toepassing Humanitair Oorlogsrecht, Voorschift No. 27-412/1, Koninklijke Landmacht, Ministerie van Defensie, 1993, pp. IX-5 and IX-6.
With respect to non-international armed conflicts, the manual restates the fundamental requirement of fair trial found in common Article 3 of the 1949 Geneva Conventions and Article 6 of the 1977 Additional Protocol II. 
Netherlands, Toepassing Humanitair Oorlogsrecht, Voorschift No. 27-412/1, Koninklijke Landmacht, Ministerie van Defensie, 1993, p. XI-1 and XI-5.
The Military Manual (2005) of the Netherlands states:
0708. Fundamental guarantees
What is the right to protection of persons not deemed prisoners of war? Primarily, these are civilians who play a direct part in hostilities, but also to mercenaries. Such persons may not be convicted or punished without prior judgment of an unbiased tribunal and due process. The same applies to persons accused of war crimes. 
Netherlands, Humanitair Oorlogsrecht: Handleiding, Voorschift No. 27-412, Koninklijke Landmacht, Militair Juridische Dienst, 2005, § 0708.
In its chapter on non-international armed conflict, the manual states:
Section 11 - Prosecutions and procedural guarantees
1071. The prosecution and punishment of offences relating to the armed conflict should be subject to the following conditions (this relates to the bearing of arms and the committing of offences and war crimes during the internal armed conflict):
- for each conviction and imposition of punishment, prior judgment by a judicial authority that meets the essential guarantees of independence and impartiality is required;
- no one may be convicted of an offence that was not punishable by law at the time it was committed;
- penal proceedings must be conducted in accordance with the internationally accepted procedural guarantees of fair and due process;
- for parties which still maintain capital punishment, the death penalty must not be imposed on persons who were younger than 18 years old at the time of committing the offence, on pregnant women or on women who are mothers of young children. 
Netherlands, Humanitair Oorlogsrecht: Handleiding, Voorschift No. 27-412, Koninklijke Landmacht, Militair Juridische Dienst, 2005, § 1071.
In its chapter on peace operations, the manual states: “A detainee may not be condemned or punished without prior judgment by an impartial court and due process.” 
Netherlands, Humanitair Oorlogsrecht: Handleiding, Voorschift No. 27-412, Koninklijke Landmacht, Militair Juridische Dienst, 2005, § 1226.
Under the International Crimes Act (2003) of the Netherlands, it is a crime to commit in an international armed conflict one of the following: grave breaches of the 1949 Geneva Conventions, including “intentionally depriving a prisoner of war or other protected person of the right to a fair and regular trial” and “intentionally … depriving a person protected by the Geneva Conventions or Article 85, paragraph 2, of Additional Protocol (I) of the right to a fair and regular trial”. 
Netherlands, International Crimes Act, 2003, Articles 5(1)(f) and 5(2)(d)(v).
Furthermore, under the Act, it is also a crime to commit, “in the case of an armed conflict not of an international character, a violation of Article 3 common to all the Geneva Conventions”, including “the passing of sentences … without previous judgment pronounced by a regularly constituted court, affording all the judicial guarantees which are generally recognized as indispensable”. 
Netherlands, International Crimes Act, 2003, Article 6(1)(d).