The North Rhein Westphalia (NRW) is the cheappest mongering area in Germany and have a huge choice of fkk, party, brothel, red light district, flatrate, ecc...
Is almost impossible to know all place, so i'll try to make a list of the most famous place.


FKK
http://www.goldentime.de/eng/
http://www.villavertigo.de
http://www.fkk-livingroom.de/
http://fkkacapulco.de/
http://www.fkkacapulco-gold.de/
https://www.dolce-vita.com/
http://www.saunaclub-magnum.de/
http://fkk-oceans.de/
http://www.samya.de/
http://www.club-mondial.de/
http://schieferhof.istmein.de/
http://www.great-palace.com/
http://www.saunaclub-babylon.com/
http://immerhappy.de/?start=true
http://saunaclub-planet-eden.de/en/home/
http://www.parksauna-residenz.de/
http://fkk-vangoch.com/
http://www.dolce-vita-raubach.de/
http://saunaclub-anubis.de/site/

FKK near border Germany-Holland
http://yinyang.nl/
http://www.sixsens.eu/


PAUSCHALCLUB
http://www.pauschalclub.de/bochum
http://www.pauschalclub.de/muenster
http://www.pauschalclub.de/dortmund


PARTYTREFF
http://www.partytreff-dorsten.de/
http://www.partytreff-xanten.nl/
http://pauschalclub69.de/page/
http://saunaclub-rheydt.de/page/
http://www.partytreff-palace.de/
http://www.partytreff-gelsenkirchen.de/
http://www.saunaclub-casino.de/


GANGBANG PARTY
http://www.erotiktreff95.de/
http://www.zhuzha.de/
http://www.seesternchen-gangbang.de/
http://www.saskia-farell.com/
http://www.intimdream.com/events
http://www.anjas-leidenschaften.de/
http://laureen-pink.com/Seite1002/Termine_Agenda


RED LIGHT DISTRICT
I think all city have some RLD but probably Dusiburg have the most famous RLD in the region
Check out Vulkanstraße, Julius-Weber-Straße and Charlotte Street.

Another famous RLD is in Cologne with The Pascha http://www.pascha.de/en/cologne/

the 3 pauschalclubs are closed and became a saunaclubs
http://www.freudenhaus.de/dortmund
https://www.saunaclub49.de/
https://www.xs-saunaclub.de/