International organizations — Immunity — Jurisdictional immunity — Nature and scope — Treaty establishing international organization — No provision for immunity from jurisdiction — Whether organization entitled to immunity under customary international law — Whether right to immunity derived from transfer of sovereignty from Member States — Immunity limited to acts performed in exercise of public functions of organization — Contract of employment — Criteria for determining whether termination of employment covered by jurisdictional immunity — Staff regulations — Validity of staff regulations restricting jurisdiction of national courts

International organizations — Immunity — Waiver — Discontinuance of waiver — Treaty providing for jurisdiction of national courts over employment disputes between international organization and its staff — Treaty also permitting international organization to issue staff regulations — Staff regulations restricting forum for employee disputes to administrative tribunal — Effect on waiver provision of Treaty — Whether staff regulations constituting unlawful modification of Treaty — The law of the Netherlands