State immunity — Jurisdictional immunity — Dispute between two foreign States concerning ownership of immovable property in third State — Competence of courts of State where property located — Scope of entitlement of defendant State to jurisdictional immunity — Restrictive theory of immunity — Acquisition or lease of premises for diplomatic use — Whether performed jure gestionis — Dispute arising in context of dissolution of Union of States and raising issues of public international law — Whether absolute entitlement to jurisdictional immunity in such circumstances

States — Union of States — Legal nature — Distinction between personal and real Union — United Arab Republic — Whether constituting fusion or succession in relation to constituent States — Dissolution of Union — Legal consequences — Dispute concerning ownership of immovable property in third State — Appropriate forum for settlement of dispute

State succession — Union of States — United Arab Republic — Whether both establishment and dissolution of Union constituting cases of State succession — Succession to property rights

Jurisdiction — Territorial — Situs of property — Dispute between two foreign States concerning ownership of immovable property in third State — Whether courts of State of situs of property competent to exercise jurisdiction — Relevance of fact that no other country’s courts competent to exercise jurisdiction — Whether defendant State entitled to claim jurisdictional immunity in such circumstances — Dispute involving questions of public international law — Appropriate forum for settlement of dispute

Diplomatic relations — Diplomatic property — Embassy building — Dispute between two foreign States concerning ownership following dissolution of Union of States — Appropriate forum for settlement of dispute

Relationship of international law and municipal law — Customary international law — Fundamental rights under State Constitution — Action to enforce property rights against foreign State — Claim to immovable property — Whether foreign State entitled to invoke jurisdictional immunity to prevent effective safeguarding of fundamental rights

Human rights — Procedure for enforcement — Fundamental rights under Brazilian Constitution — Right to property — Claim against foreign State for return of immovable property — Whether jurisdictional immunity may be invoked as a bar to claim — The law of Brazil