Règle correspondante
Sweden
Practice Relating to Rule 14. Proportionality in Attack
Sweden’s IHL Manual (1991) considers that the principle of proportionality as contained in Article 51(5)(b) of the 1977 Additional Protocol I reflects customary international law. 
Sweden, International Humanitarian Law in Armed Conflict, with reference to the Swedish Total Defence System, Swedish Ministry of Defence, January 1991, Section 3.2.3, p. 19.
Under Sweden’s Penal Code (1962), as amended in 1998, “initiating an indiscriminate attack knowing that such attack will cause exceptionally heavy losses or damage to civilians or to civilian property” constitutes a crime against international law. 
Sweden, Penal Code, 1962, as amended in 1998, Chapter 22, § 6.
In its written statement submitted to the ICJ in the Nuclear Weapons case in 1995, Sweden stated: “In the case of an attack on a military target, disproportionately substantial damage may not be inflicted on the civilian population or on civilian property.” 
Sweden, Written statement submitted to the ICJ, Nuclear Weapons case, 20 June 1995, p. 3; see also Written statement submitted to the ICJ, Nuclear Weapons (WHO) case, 2 June 1994, p. 3.
In 2007, in an answer to a question in Parliament, the Swedish Minister for Trade stated: “It is prohibited to carry out attacks against military targets that entail injuries to the civilian population that are disproportionally extensive compared to the military value of the attack.” 
Sweden, Answer by the Minister of Trade to a Parliamentary interpellation on the sale of cluster munitions to the United States, 13 November 2007, Parliamentary Protocol 2007/08:23, § 18, Anf. 124.
Humanitarian law is based on a number of fundamental principles. They are apparent in current treaties and customary law and express the core of humanitarian law. They concern the principles of distinction, proportionality and precaution, the prohibition on causing superfluous damage and unnecessary suffering and the principle of non-discrimination as well as the so called Martens Clause. 
Sweden, Government Bill 2013/14:146 on criminal liability for genocide, crimes against humanity and war crimes, 20 February 2014, p. 33.
The annual report of the Secretary-General paints a gloomy picture of the situation around the world for children in armed conflict. ISIL has been listed as violating all triggers of violence against children, a result of their appalling atrocities. In Syria, the systematic use of indiscriminate aerial weapons, such as barrel bombs, account for the overwhelming majority of civilian casualties, including children. This cannot be allowed to continue. And during hostilities in Gaza last summer, civilians, including children, bore the brunt of the suffering. At least 540 Palestinian children were killed and hospitals and schools were severely damaged or destroyed, including UN facilities. The scale of the impact on children was unprecedented and unacceptable.
These facts and all other incidents listed in the report are utterly disturbing and raise serious concern about the observance of the rules of international humanitarian law, including the [principle] of … proportionality. 
Sweden, Statement by the permanent representative of Sweden at the UN Security Council Open Debate on Children and Armed Conflict made on behalf of Finland, Iceland, Norway and Sweden, 18 June 2015.