The general area is known as Schipperskwartier which has recently been 'developed' or 'tamed'. The area of interest still is between St-Paulusstraat and Brouwersvliet, including Verversrui, Vingerlingstraat and Schippersstraat. The Villa Tinto is a major establishment in the area - more information on this link
At the southern end of the Aarschotstraat, there are also windows to be found on the rue de la prairie which is off to the left (going South) and the Plantenstraat/rue des plantes and rue Linné which are off to the left of the Rue de la prairie
Avenue Louise, north end (Place de Stephanie)
Some action adjacent to the Gare du Midi too seemingly, near/in cafes at the junction of Av. Fonsny and Engellandstraat/rue d'Angleterre.
'Le triangle de Charleroi' bounded by the rue Moulin, rue Desandrouin and rue Fenderie
The parking place at d'Heppignies
Gosselies near Charleroi has a street with window girls.
Roadside brothels Deinze Steenweg N43
Two streets near to each other :-
Pieter Vanderdoncktdoorgang (300 meters north of Gent Zuid railway station (and City Shoppingcentre Gent Zuid), also referred to as glazen straatje presumably because of its arcade nature (see picture).
Belgradostraat, a hundred meters or so further North.
situation in a bit of flux at the moment, I believe - follow this link for further information
Confused about the current situation - have various addresses but unsure about their current validity. Addresses include Langestraat (north of the ferry port), Hazegras (adjacent to the railway station), Fregatstraat, Vrijhavenstraat, Oesterbankstraat.
Along the N3 road (between Sint-Truiden and Liège) "Chaussee d'Amour", colloquially, apparently) women ply their trade behind windows.
Stories tell of traffic being regularly held up because of this 'distraction' and of a higher-than-expected accident rate along this route.