Section III
Other crimes
Article 18
Recruitment of mercenaries
1. Anyone who recruits or attempts to recruit mercenaries:
(a) For military service on behalf of a foreign State;
(b) For any national or foreign armed organisation that plans to use violent means to overthrow the lawful government of another State or to undermine the independence, territorial integrity or the normal functioning of the institutions of that State;
shall be punished with a term of imprisonment of 1 to 5 years.
2. A mercenary is any person who is considered as such by virtue of international law.
National penalties
Unique provision - other crimes
EDIT.