Article 23 1.

Air fares and air rates available to the general public shall include the applicable conditions when offered or published in any form, including on the Internet, for air services from an airport located in the territory of a Member State to which the Treaty applies. The final price to be paid shall at all times be indicated and shall include the applicable air fare or air rate as well as all applicable taxes, and charges, surcharges and fees which are unavoidable and foreseeable at the time of publication. In addition to the indication of the final price, at least the following shall be specified:

where the items listed under (b), (c) and (d) have been added to the air fare or air rate. Optional price supplements shall be communicated in a clear, transparent and unambiguous way at the start of any booking process and their acceptance by the customer shall be on an ‘opt-in’ basis.