Chapter II
Crimes
Section I
Crime of genocide and crimes against humanity
Article 9
Crimes against humanity
Anyone who commits any of the following acts as part of a widespread or systematic attack directed against any civilian population:
(g) Using force, the threat of force or another form of coercion, or taking advantage of a coercive environment or the victim’s lack of decision-making capacity:
(i) To cause the penetration, however slight, of any part of the body of the victim or of the perpetrator with any part of the body of the perpetrator, the victim, a third party or any object;
shall be punished with a term of imprisonment of 12 to 25 years.
Rape - crimes against humanity
EDIT.