Artikel 20

The Contracting States, recognising the necessity in general of leaving tariffs sufficient flexibility to permit of their being adapted as closely as possible to the complex needs of trade and commercial competition, retain full freedom to frame their tariffs in accordance with the principles accepted by their own legislation, provided that this freedom is exercised without detriment to international traffic.
They undertake to apply to international traffic tariffs which are reasonable both as regards their amounts and the conditions of their application, and undertake to refrain from all discrimination of an unfair nature directed against the other Contracting States, their nationals or their vessels.
These provisions shall not prevent the establishment of combined rail and sea tariffs which comply with the principles laid down in the previous paragraphs.