If you do not plan to fly from Germany to France, taking a train from Berlin to Brussels is the best way to get between the two cities when you are visiting Europe.
Several companies run trains from Berlin to Brussels, including Deutsche Bahn and Thalys. They offer departures every one to two hours from the morning until the afternoon.
All trains leave Berlin Hauptbahnhof station for Brussels Midi-Zuid station. Both are major train stations, and are connected to all forms of onward transportation.
There are no direct trains between these cities, so you will have to connect in a place like Amsterdam or Cologne on the way. The total journey on trains from Berlin to Brussels takes 6 hours and 45 minutes if you take a fast service that only requires on change.
Train ticket fares from Berlin to Brussels start at 59 euros for singles in second class and 69 euros singles in first class if you buy train tickets online in advance and take advantage of Savings Fares. Seat reservations are mandatory on some services, and are usually included in the ticket fare.