The individual in international law — Nationality — Double nationality — Acquisition of second nationality — Whether nationality of origin lost — Tunisian national settling in Israel and acquiring Israel nationality — Tunisian Nationality Code providing for loss of Tunisian nationality on acquisition of another nationality — Requirement of formal declaration — Whether Tunisian nationality retained — “Effective nationality” — Hague Convention of 1930 (Article 5) — Need for third States to determine “active nationality” — Criteria for such determination — Presumptions — Whether effective nationality Tunisian or Israeli — The law of France