Night Train Map with all regularly served night train destinations in Europe
There is a clear lack of connection toward France and Spain.
EDIT: Paris is of course well connected, but southern France and Spain are not. I live in Zurich and it's quite easy to go north, south, and east by train, but going south-west towards Marseille, Toulouse, Barcelona is really inconvenient. And it's not just about Zurich, because doing so from Milan or Frankfurt, I would guess, is the same. However I heard of plans for a Zh-Barcelona night train, does anybody know anything about it?