CNN kindly links to the judgment.
As is usual with German judgments it’s difficult to work out exactly what the parties were arguing (we just have a brief statement that the defendant argued that the terms were not properly incorporated and/or were invalid; without setting out why they said they were invalid).
The judgment sets out what the judge thought about it and she ruled that the terms were validly incorporated, were something that travellers could expect to be in an airline’s terms but were nevertheless invalid because they breach the requirement for transparency in Article 307 Abs. 1 S. 2 BGB.
She decided that what that requires is that the traveller be able to determine - at the point of booking the ticket- what the additional charge for not completing the booked journey would be.
Lufthansa doesn’t have a system letting you do that, they just tell you that they will charge you what the price for the actual journey would have been if you’d booked it on the day.
She says the traveller has got no way of knowing what that will be when they book and of course, no one can check the price claimed by Lufthansa now.
I’m not sure that holds up because the traveller can presumably just plug his actual journey into the booking system and get a price?
She also suggests that even if the airline is entitled to recalculate the ‘actual’ journey, that should be on the basis of a journey Oslo-Frankfurt-Seattle-Frankfurt, rather than Oslo-Frankfurt-Seattle-Frankfurt-Berlin.
That’s on the basis that the Frankfurt-Berlin journey was legitimately booked and taken. He could quite happily have got out in Frankfurt and booked with another carrier to go to Berlin and Lufthansa wouldn’t have been able to claim for the flight to Berlin.