I'm trying to figure out what this is. I went to LUX and booked a overnight reservation (CNL: Munich to Venice). This was the 11.50 euro reservation (I have a rail pass). What we ended up with was a compartment for 6 people where the 'seat/couch' folded up so we ended up with 6 beds and slept nicely, so basically a couchette. I'm looking to travel from Metz to Berlin now and and DB Bahn the 11.50 euro option is for a 'Day Couch, 1 person in compartment'. I've been looking it up and I have yet to find anything that says my first experience is what I will get again. All second class also.
Thanks for the help.
Chris, There is no guarantee you'd get the same windfall. Take it to chance, have no expectations and assume it will be a normal seat-couch.