Article 17
Relations with countries outside the Union
1. Offices of the Union which have relations with countries situated outside the Union are to lend their assistance to all the other Offices of the Union:
2. The charges for the total sea transit, within and without the Union, may not exceed 15 francs per kilogramme of letters and post cards and 1 franc per kilogramme of other articles. If occasion arise these charges are divided, in the ratio of distances, between the Offices taking part in the sea conveyance.
3. The charges for transit, by land or sea, without as well as within the limits of the Union, on the articles to which the present Article applies are established in the same manner as the transit charges relating to articles exchanged between Union countries by means of the services of other countries of the Union.
4. The transit charges on articles for countries outside the Postal Union are payable by the Office of the country of origin, which fixes the postage rates in its services for the said articles, but these rates may not be lower than the normal Union tariff.
5. The transit charges on articles originating in countries outside the Union are not payable by the Office of the country of destination. That Office delivers without charge articles transmitted to it as fully prepaid; it charges unpaid articles double the prepaid rate applicable in its own service to similar articles addressed to the country where the said articles originate, and insufficiently prepaid articles double the deficiency; but the charge may not exceed that which is levied on unpaid articles of the same nature, weight, and origin.
6. With regard to responsibility in the matter of registered articles, the articles are treated: