The Federal Court of Justice of Germany (Bundesgerichtshof) decided that all fees have to be included in the price of the ticket right away, if not every customer can avoid them.
This includes service charges that would only lapse when choosing a certain means of payment. It is not sufficient to show those fees in the last step of the booking process. Consumers should be able to make an effective price comparison when booking a flight.
Please find below the full text of the verdict (German):