[raverbashing]

And by a comment on the page, the flight also takes not only MEPs but members of the EC as well

[jen20]

One assumes that since it has an LH flight number, anyone who wants to pay for it could book the flight.

[raverbashing]

Possibly, but not necessarily (based only on the flight number).

Fun fact, all flights (from commercial airlines) have a flight number, but those are not always sold. They might be charters or ferry/repositioning flights. (And while it might make sense to sell a repositioning flight - sometimes it's done on short notice or the airline doesn't want to assign cabin crew to those flights)

[jen20]

Quite aside from the flight number, the article shows you can book it, and indicates prices and seat availability for one of the dates it runs.