Related Rule
Germany
Practice Relating to Rule 2. Violence Aimed at Spreading Terror among the Civilian Population
Germany’s Military Manual (1992) states that “measures of intimidation or of terrorism” are prohibited. 
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 Konflikten – Handbuch, August 1992, § 507; see also ZDv 15/1, Humanitäres Völkerrecht in bewaffneten Konflikten – Grundsätze, DSK VV230120023, Bundesministerium der Verteidigung, June 1996, § 403.
In 2009, in reply to a Minor Interpellation in the Bundestag (Lower House of Parliament) titled “Investigation of serious violations of international humanitarian law in the recent Gaza war”, Germany’s Federal Government wrote:
9. How does the Federal Government assess the firing of rockets at towns and villages in Southern Israel by armed Palestinian groups in Gaza under international law?
Which specific provisions of international humanitarian law were violated by the Palestinian side?
The Federal Government condemns any act of violence and all acts of hostilities directed against civilians, as well as acts of terror. … Using violence or threatening to use violence with the primary purpose of spreading terror amongst the civilian population … [is] prohibited. 
Germany, Lower House of Federal Parliament (Bundestag), Reply by the Federal Government to the Minor Interpellation by the Members Winfried Nachtwei, Kerstin Müller (Cologne), Jürgen Trittin, other Members and the Parliamentary Group BÜNDNIS 90/DIE GRÜNEN, BT-Drs. 16/12673, 20 April 2009, p. 4.