I am located in Köln, right next to Düsseldorf and have a real world understanding of the city, having been there myself many times.
A great city for an Alt bier and a walk along the promenade!
German is my second language and I can provide proof of my proficiency from Berlitz language school and German references as I have been living here since 2012.
I look forward to hearing from you.
Truly,
James