You might feel out of place today. Didn't they just adjust the speed limit in the inner circle of Brussels town to 20 km/h (12.5 mph) for all non-pedestrian traffic? Also you would need to register your vehicle for the light emission zone for all of the Brussels Capital Region, or get a 350 euro fine (luckily, just one for the duration of your stay). Cars rented in Belgium will have been accounted for I assume, but about foreign cars I wouldn't be too sure. Welcome to the Capital of Europe!