International criminal law (ICL) is a branch of international law that establishes the criminal responsibility of individuals for Crimes against humanity, War crimes, Genocide and the crime of aggression [1]. It allows for the prosecution not only of direct perpetrators, but also of those involved in the planning, organisation or execution of these crimes, as well as the superiors, political or military leaders, who ordered or condoned them [2].

Under international law, states have the primary responsibility for preventing and prosecuting these crimes before domestic courts. This involves, in particular, incorporating international crimes into national legislation, conducting effective investigations, prosecuting those responsible and ensuring appropriate penalties. In certain cases, given the gravity of these crimes, states may exercise jurisdiction regardless of the place where the acts were committed or the nationality of the persons concerned, in accordance with the principle of Universal jurisdiction.

In this context, the Rome Statute of the International Criminal Court (ICC) constitutes a central reference. As the founding treaty of the ICC (adopted in 1998 and entered into force in 2002), it is supplemented by two key documents: the Elements of Crimes, which set out the constituent elements of each crime, and the Rules of Procedure and Evidence, which govern the conduct of investigations and prosecutions, including the admissibility of evidence and the protection of victims and witnesses. Together, these instruments provide a unique guide for national courts, particularly as they build on the unprecedented developments stemming from earlier international criminal institutions, notably the Nuremberg and Tokyo Military Tribunals and the International Criminal Tribunals for the former Yugoslavia and Rwanda.

The system established by the Rome Statute is founded on the principle of complementarity: the ICC intervenes only when states are unwilling or unable to conduct effective investigations and prosecutions themselves. Its jurisdiction is focused on "those bearing the greatest responsibility". The Court’s judicial decisions, including its interpretations of crimes and other forms of legal recognition, particularly regarding Sexual violence (including conflict-related sexual violence) and Gender-based violence (SGBV), serve as a key reference and exert significant influence, especially in the context of conflict or genocide [3].

Building on the advances initiated by earlier international criminal tribunals, recent decades have seen significant developments in the recognition and understanding of the nature, scale and gravity of SGBV, the contexts in which it is committed, and its consequences for survivors/victims, their families, their communities, and society as a whole. International criminal law and international criminal justice have thus played a major role in strengthening protection against such violence and in interpreting the norms of International Humanitarian Law and International human rights law.

Relevant sources within international criminal law also include the policy papers issued by the Office of the Prosecutor of the ICC. While not legally binding and specific to that body, they reflect the most recent developments in the interpretation, investigation and prosecution of international crimes, particularly in relation to Sexual violence (including conflict-related sexual violence) and Gender-based violence (SGBV). They include policies on gender-based crimes, gender-based persecution, crimes against children and crimes of slavery.