Via Airliners.net:

To increase the travel comfort on intercontinental night flights, Lufthansa is thinking about a separate sleeping area within Economy Class. There, you would have the possibility to sleep in beds with an angle of 180? (Full Flat). This option could be booked instead of a seat.
In the future, when booking a night flight with Lufthansa from Johannesburg to Frankfurt, would you generally be interested in booking into the sleeping area instead of a seat in Economy Class?