Police said a go-slow procession of 627 cabs several kilometres long drove through the city before stopping at the headquarters of the European Union.
They hooted their horns, set off fireworks and blocked roads around the EU building for several hours, causing huge traffic jams.
US-based Uber allows non-professional drivers to become chauffeurs-for-hire at rates far lower than normal taxi rides.
It is banned in Belgium but operates instead under the name UberPop under a law which allows individual vehicle hire.
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"Either Uber is banned in all towns and countries around the world, or it is a profession that requires rules."
Around 100 French taxi drivers travelled to Brussels to take part in the protest.
Uber, which operates in about 250 cities in 50 countries, has become an object of scorn from traditional taxi companies fighting for survival against the rise of the Silicon Valley challenger, founded in 2009.