Règle correspondante
Germany
Practice Relating to Rule 14. Proportionality in Attack
Section B. Determination of the anticipated military advantage
Germany’s Military Manual (1992) states: “The term ‘military advantage’ refers to the advantage which can be expected of an attack as a whole and not only of isolated or specific parts of the attack.” 
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, § 444.
In 2010, in the Fuel Tankers case, the Federal Prosecutor General at Germany’s Federal Court of Justice investigated whether war crimes or other crimes under domestic law had been committed in the course of an airstrike which was ordered by a colonel (Oberst) of the German armed forces against two tankers transporting fuel for the International Security Assistance Force in Afghanistan stolen by the Taliban near Kunduz and which resulted in the deaths of a number of civilians. The Federal Prosecutor General stated:
Pursuant to § 170 para. 2 StPO [Penal Procedure Code], the investigation proceedings which were initiated by the order of 12 March 2010 against Colonel (Oberst) Klein and Company Sergeant Major (Hauptfeldwebel) Wilhelm due to suspected offences under the VStGB [International Crimes Code] and other offences are to be terminated as a result of the investigations conducted and based on the sources of information set out hereafter and on the reasons given in detail hereafter. 
Germany, Federal Court of Justice, Federal Prosecutor General, Fuel Tankers case, Decision, 16 April 2010, p. 1.
The Federal Prosecutor General also stated:
Criminal responsibility under § 211 StGB [i.e. for murder under Germany’s Penal Code]
b)
Colonel (Oberst) Klein’s actions were lawful under international law and therefore justified under domestic criminal law …
cc)
Even considering the fact that the bombing killed civilians to be protected under the international law of armed conflict, the order to attack was lawful under international law.
(1)
… International humanitarian law only prohibits … attacks … against a military objective if at the time of the order to attack the anticipated civilian damage is out of proportion (“excessive” see Art. 51 para. 5 sub-para. b AP I [the 1977 Additional Protocol I]) to the anticipated concrete and direct military advantage (see ICRC Customary International Humanitarian Law, 2005 – hereafter ICRC Customary IHL [Study] – p. 46ff). …
(2)
The standard of prohibiting excess first requires a military advantage of a tactical nature … , such as the destruction or weakening of hostile troops or their means of combat, or territorial gain … Collateral damage such as the death of civilians is not out of proportion merely because the military advantage is only a short-term advantage which does not decide the conflict. Thus, the bombarding of a broadcasting centre by NATO in Belgrade with the foreseeable result of numerous civilian deaths was not considered to be out of proportion, even though the anticipated tactical advantage only lay in the interruption of the adversary’s telecommunication for a few hours (Final Report to the Prosecutor by the Committee established to review the NATO Bombing Campaign against the Federal Republic of Yugoslavia, marginal no. 78). In the present case the bombing pursued to military goals, namely the destruction of the fuel tankers robbed by the Taliban and of the fuel as well as the killing of the Taliban, including not least the high-level regional commander of the insurgents. The anticipated military advantage, namely on the one hand the final prevention of using the fuel and the fuel tankers as “driving bombs” or to fuel the insurgents’ militarily used vehicles and on the other hand the at least temporary disruption of the Taliban’s regional command structure fall within the usual, recognized tactical military advantages … The fact that the goal mentioned in second place was not fully achieved is irrelevant for the legal assessment because the expectations at the time of the military action based on the facts are decisive (“ex ante view”, see ICRC Customary IHL [Study] p. 50 …) …
(4)
Even if the killing of several dozen civilians would have had to be anticipated (which is assumed here for the sake of the argument), from a tactical-military perspective this would not have been out of proportion to the anticipated military advantages. The literature consistently points out that general criteria are not available for the assessment of specific proportionality because unlike legal goods, values and interests are juxtaposed which cannot be “balanced” … Therefore, considering the particular pressure at the moment when the decision had to be taken, an infringement is only to be assumed in cases of obvious excess where the commander ignored any considerations of proportionality and refrained from acting “honestly”, “reasonably” and “competently” … This would apply to the destruction of an entire village with hundreds of civilian inhabitants in order to hit a single enemy fighter, but not if the objective was to destroy artillery positions in the village … There is no such obvious disproportionality in the present case. Both the destruction of the fuel tankers and the destruction of high-level Taliban had a military importance which is not to be underestimated, not least because of the thereby considerably reduced risk of attacks by the Taliban against own troops and civilians. There is thus no excess. 
Germany, Federal Court of Justice, Federal Prosecutor General, Fuel Tankers case, Decision, 16 April 2010, pp. 63–66 .
Upon ratification of the 1977 Additional Protocol I, Germany stated that the term “military advantage” as used in the proportionality test of Articles 51 and 57 of the Protocol was understood to refer to the advantage anticipated from the attack considered as a whole and not only from isolated or particular parts of the attack. 
Germany, Declarations made upon ratification of the 1977 Additional Protocol I, 14 February 1992, § 5.