Article 6 Montreal Convention
Article 6 of the Montreal Convention (Convention For the Unification of Certain Rules for International Carriage by Air) is titled Document Relating to the Nature of the Cargo. It is under Chapter II (Documentation and Duties of the Parties Relating to the Carriage of Passengers, Baggage and Cargo).
The consignor may be required, if necessary to meet the formalities of customs, police and similar public authorities, to deliver a document indicating the nature of the cargo. This provision creates for the carrier no duty, obligation or liability resulting therefrom.
See also: Article 5 Montreal Convention