Just an FYI in case it might impact your seat selection:

Yesterday on flight LH446 to DEN from FRA, the front cabin (C) was too warm (though it was several hours into the flight before the issue arose). This was the same problem I experienced a little more than 2 weeks ago on my outbound on 447 (probably the same plane); I heard a number of others grumbling about the problem as well. In both situations, the FAs explained that the second cabin (also C) was too cold, and they could not do much to adjust the temp without adversely affecting the other cabin. From the FA yesterday, this is not the typical situation in the A340-600; thus the problem may be limited to this aircraft.

On both flights, the FAs did offer me a different seat, but I declined due to the hassle of repacking my stuff and finding overhead space near the other seat (and moving away from a window seat).

Maybe others taking these flights could report whether/when the situation appears to be corrected?