Related Rule
Germany
Practice Relating to Rule 84. The Protection of Civilians and Civilian Objects from the Effects of Incendiary Weapons
Germany’s Military Manual (1992) defines incendiary weapons in accordance with the 1980 Protocol III to the Convention on Certain Conventional Weapons and states:
422. When incendiary weapons are used, precautions shall be taken which are practicable or practically possible taking into account all circumstances ruling at the time, including humanitarian and military considerations.
423. The civilian population as such, individual civilians and civilian objects shall be granted special protection. They shall never be made the object of attack by incendiary weapons.
424. It is prohibited in all circumstances to make any military objective located within a concentration of civilians the object of attack by incendiary weapons.
425. It is further prohibited to use incendiary weapons against forests or other kinds of plant cover except when such natural elements are used to cover, conceal or camouflage a military objective, or are themselves military objectives. 
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, §§ 420–425.
In 2009, in reply to a Minor Interpellation in the Bundestag (Lower House of Parliament) entitled “Investigation of serious violations of international humanitarian law in the recent Gaza war”, Germany’s Federal Government wrote:
14. Can the Federal Government confirm or deny that ammunition with white phosphorous has been used in densely populated areas (e.g. Gaza City) and against civilian installations (e.g. the UN), and how does the Federal Government assess such use under international humanitarian law?
The Federal Government is aware of allegations that Israel has used phosphorous weapons in a way that violated international law. This is the subject of a number of investigations, including by Israel. The Federal Government has no information of its own on whether such weapons were used. Smoke ammunition which includes white phosphorus is not prohibited as such under international humanitarian law. But its use must comply with the general rules of international humanitarian law. Hence a direct use against civilians would be unlawful and an indiscriminate attack which does not distinguish between legitimate objectives and civilians, or an attack against a military objective which must be expected to cause loss of civilian life that is out of proportion to the concrete and direct advantage are all 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. 6.
In 2010, in its objection to the reservation by the United States of America to the 1980 Protocol III to the Convention on Certain Conventional Weapons, Germany stated:
The Federal Republic of Germany has examined the reservation submitted by the United States of America on 21 January 2009 concerning Protocol III on Prohibitions or Restrictions on the Use of Incendiary Weapons of the Convention on Prohibitions or Restrictions on the Use of Certain Conventional Weapons which may be deemed to be Excessively Injurious or to have Indiscriminate Effects (CCW) [in which the United States of America reserves the right to use incendiary weapons against military objectives located in concentrations of civilians where it is judged that such use would cause fewer casualties and/or less collateral damage than alternative weapons, but in so doing will take all feasible precautions with a view to limiting the incendiary effects to the military objective and to avoiding, and in any event to minimizing, incidental loss of civilian life, injury to civilians and damage to civilian objects] and raises an objection to it.
The Federal Republic of Germany understands that the intention of the reservation submitted by the United States of America is to cause fewer casualties and/or less collateral damage.
However, the Federal Republic of Germany is of the opinion that the reservation is incompatible with the object and purpose of the CCW and Protocol III and that it would leave the decision of whether or not the respective norms of the Protocol should be applied to the discretion of a military commander.
This objection does not preclude the entry into force of Protocol III between the Federal Republic of Germany and the United States of America. 
Germany, Objection to the Reservation by the United States of America to the 1980 Protocol III to the Convention on Certain Conventional Weapons, 1 February 2010.