States as international persons — In general — Recognition of acts of foreign States and Governments — Taking of property — Expropriation of immovable property in Budapest by Hungarian Government for French Legation — Property formerly occupied by French Legation under lease giving jurisdiction in respect of disputes to French courts — Action in France by former owners and lessors against French State for payment of rent due from date of expropriation — Whether French courts competent to adjudicate — The law of France.