State immunity — Jurisdictional immunity — Commercial Office of Portugal in Brussels — Dispute concerning payment for translation — Whether Portuguese State entitled to jurisdictional immunity — Distinction between acts performed jure gestionis and jure imperii — Applicability on facts of case

Diplomatic relations — Immunity — Diplomatic agent — Immunity from civil jurisdiction — Vienna Convention on Diplomatic Relations, 1961 — Article 31 — Immunity limited to official functions — Scope of functions of diplomatic mission — Whether Article 3 of Convention contains exhaustive list of functions — Waiver of immunity — The law of Belgium