International humanitarian law is the law applicable during armed conflict. According to this assertion, international humanitarian law applies from the outset of an armed conflict, whether international or non-international, until its end. But in a society where the use of force must be the exception, conceding that international humanitarian law applies inevitably creates unease. What is more, the implementation of international humanitarian law is generally surrounded by controversy.

Generally speaking, the applicability of international humanitarian law is at stake whenever armed violence occurs. Concluding that international humanitarian law applies to a given situation has at least two distinct consequences. On the one hand, it means that the situation in question justifies taking measures that derogate from ordinary law, which are the subject of specific regulations. On the other hand, the people who may be affected by this situation benefit from a certain number of protections that are specific to this exceptional situation.

The application of international humanitarian law therefore offers specific protection and, as a corollary, creates specific obligations for States and other actors involved in an armed conflict. The provisions of international humanitarian law contained in some one hundred international treaties are not only numerous but also extremely detailed and demanding. As a result, asserting the applicability of international humanitarian law against the parties to a conflict has serious consequences for them, but also provides additional guarantees for people requiring protection in this particular context.