There are three main areas in Brussels where red light activities happen. This page lists the streets and a little about prices for sex in Brussels. The area around the northern train station Gare du Nord could be considered the main Brussels red light district. But it is also the most dirty one.
Some of it is in business during the day, but it is most alive at night. Info about prices is lower on this page. The main red light street is Rue d'Aerschot. It is the street you will be on as you exit the station. It is long and goes from south to north. After midnight the windows and shops light up with red neon lights and women start attracting custommers. The larger street nearby - Rue de Brabant, is filled mainly with cheap clothes shops.
But there are also some kebab and fast food shops. No red windows here. But it has small night shops which supply tobacco, alcohol and snack foods. These stay open until the morning hours. It is in the southern part of this red light district.
Nearby streets like Rue des Plantes or Rue de la Prairie also have some. It is full of graffity and street people.
If you want a cleaner experience then visit one of other Brussels RLD described below. If you want to meet asian women, visit this area. There is less prostitution here then around North train station, but it is also much cleaner and more safe looking. It is the area between Brussels Noordstation and the old city center. Not far away from both. But you need to go to specific streets.
