Crimes Against Humanity and War Crimes Act 2000
8. A person who is alleged to have committed an offence under section 6 or 7 may
be prosecuted for that offence if
(a) at the time the offence is alleged to have been committed,
(ii) the person was a citizen of a state that was engaged in an armed conflict against Canada, or was employed in a civilian or military capacity by such a state,
Unique provision - jurisdiction
EDIT.