Related Rule
Croatia
Practice Relating to Rule 108. Mercenaries
Croatia’s Criminal Code (1997), as amended to 2006, states:
A mercenary is a specially recruited person in the country or abroad to fight in an armed conflict or to participate in a joint act of violence aimed at overthrowing the government or subverting in some other way the constitutional order or the territorial integrity of a country, who is neither a national of the parties to the conflict nor living in the territory controlled by a party to the conflict, who is not a member or the armed forces of a party to the conflict or of the party in whose territory an action is undertaken and who is not sent by a country which is not a party to the conflict as an official member of its armed forces but who is motivated to take part in the hostilities only for his personal gain significantly higher than the remuneration promised or paid to combatants of a similar rank or profession in the armed units of the party participating in the hostilities. 
Croatia, Criminal Code, 1997, as amended to 2006, Article 89(35).
[emphasis in original]
Croatia’s Criminal Code (1997), as amended to 2006, states: “Whoever, with an aim to acquire material gain, directly participates as a mercenary in an armed conflict or a joint act of violence shall be punished by imprisonment for six months to five years.” 
Croatia, Criminal Code, 1997, as amended in June 2006, Article 167b(2).