Originally Posted by Track

The Paris-Brussels-Amstedam/Cologne route is operated by Thalys (jointly owned by the 4 national railroads, which also own - separately - the train sets) and use TGV train sets specially adapted for the route (electrical and train-control systems, etc.). There have never been separate Thalys and TGV operators on the route. It was never branded a TGV route, and today still the trains have "Thalys" nicely painted on the sides. The train numbers also are shown as "THAxxx.)