There are three bands under this name.
(1) Belgian synth-pop/electro/new wave band of the 1980's founded by Patrick Nebel. They had one very big hit in 1984 with their track "Beats Of Love". Afterwards the band released 2 more albums, but never had the same kind of success with these. The band comes to an end in 1986 due to the death of founding member Patrick Nebel.
(2) Nacht Und Nebel comes from Canadian lands and represents extremist nsbm. `The Drowning Source ...of Triumph` is their debut release of a winter rehearsal - `a single moment crystalized through music and alcohol` as they are saying. Musically you should expect very raw grim black metal. The vocal is horribly sick and shrieking is vey high.
(3) Nacht Und Nebel - Polish band from Wrocław.