States as international persons — State succession — Succession to rights — Algerian accession to independence — Declaration of Principles concerning Economic and Financial Co-operation 1962, Article 18 — Social security funds — Preferential claim for unpaid contributions in Company winding-up proceedings, given by legislation applicable prior to independence — Winding-up proceedings in France — Whether new Algerian social security fund succeeds to preferential right of predecessor organization — Distinction between debts accruing before and after the date of independence — The law of France