A court in Cologne ruled in favour of Lufthansa that customers must use all flight coupons in sequence as booked. This overrules a previous ruling of a lower court according to which customers are free to use tickets in full in part, as they like. Seems like the situation is far from clear now, as today's ruling largely agreed with LH's argument that national markets should be protected.
http://www.spiegel.de/reise/aktuell/...640422,00.html
(Sorry, link in German only.)