International law — Relation to municipal law — Inter — Governmental Agreement — Exchange of letters annexed to Agreement — Letters not published as provided by constitutional law of country of forum — Whether parties to proceedings in country of forum entitled to rely on content of letters — The law of France.

Treaties — Operation of — Inter-Governmental Agreement — Exchange of letters annexed to Agreement — Letters not published as provided by constitutional law of country of forum — Whether parties to proceedings in country of forum entitled to rely on content of letters — The law of France.