Related Rule
Germany
Practice Relating to Rule 100. Fair Trial Guarantees
Section A. General
Germany’s Military Manual (1992) provides that civilians “shall have the right to a regular and fair judicial procedure”. 
Germany, Humanitarian Law in Armed Conflicts – Manual, DSK VV207320067, edited by The Federal Ministry of Defence of the Federal Republic of Germany, VR II 3, August 1992, English translation of ZDv 15/2, Humanitäres Völkerrecht in bewaffneten KonfliktenHandbuch, August 1992, § 518.
The manual further states that “prevention of a fair and regular trial” is a grave breach of IHL. 
Germany, Humanitarian Law in Armed Conflicts – Manual, DSK VV207320067, edited by The Federal Ministry of Defence of the Federal Republic of Germany, VR II 3, August 1992, English translation of ZDv 15/2, Humanitäres Völkerrecht in bewaffneten KonfliktenHandbuch, August 1992, § 1209.
Germany’s Law Introducing the International Crimes Code (2002) provides a punishment for anyone who, in connection with an international or non-international armed conflict:
imposes on or enforces against a person protected under international humanitarian law a severe punishment, particularly the death penalty or imprisonment, without such person having been convicted by an impartial and regularly constituted court affording the judicial guarantees required under international law. 
Germany, Law Introducing the International Crimes Code, 2002, Article 1, § 8(1)(7).
In 2005, in a reply to a question by a Member of the Bundestag (Lower House of Parliament), a German Minister of State, Federal Foreign Office, wrote:
How does the Federal Government assess the legal view of the United States that so-called unlawful combatants are not entitled to the rights according to the Additional Protocols to the Geneva Convention?
As is known, the status of the detainees of the United States in Guantanamo and at other places is contentious. The Federal Government is still of the view that, independent of a subsequent status definition, these detainees are to be treated like prisoners of war, i.e. in compliance with international humanitarian law. This comprises: humane treatment, respect for their persons and their honour, protection against acts of violence and intimidation, the right to medical treatment and, as regards trials, guarantees in line with the rules of law. The Federal Government also adheres to its view that the status of the detainees, contentious under international law, requires clarification and an expeditious solution. 
Germany, Bundestag, Stenographic Report, 7th Sitting, Berlin, Wednesday, 14 December 2005, Written reply by Minister of State, Federal Foreign Office, Plenarprotokoll 16/7, 14 December 2005, Anlage 21, p. 407.