Article 10Upgrading and downgrading
(1.
If an operating air carrier places a passenger in a class higher than that for which the ticket was purchased, it may not request any supplementary payment.
(2.
If an operating air carrier places a passenger in a class lower than that for which the ticket was purchased, it shall within seven days, by the means provided for in Article 7(3), reimburse
(a)
30 % of the price of the ticket for all flights of 1500 kilometres or less, or
(b)
50 % of the price of the ticket for all F1... flights between 1500 and 3500 kilometres, or
(c)
75 % of the price of the ticket for all flights not falling under (a) or (b) F2....