A fire broke out at a snack bar on Avenue de la Couronne in Ixelles on Monday afternoon, prompting extensive efforts by firefighters.
Flames spread through the building's extraction system, reached the roof, and engulfed the snack bar.
According to the Brussels Fire Brigade, firefighters, medical teams and police were called to the scene at around 13:10.
The building houses a ground-floor food business and two floors of apartments.
When emergency crews arrived, heavy smoke was pouring from the premises. Fire brigade said all customers had already evacuated the snack bar and no residents were inside the building at the time.
The fire affected the cooking area, extraction hood, and ventilation duct before spreading towards the rear of the building, where flames became visible.
Firefighters said the blaze travelled through the extraction duct up to the flat roof at the back of the top floor.
Part of the roof, rear cladding and insulation had to be dismantled to fully extinguish the fire and prevent it from spreading further.
Cleanup and cooling operations continued for some time afterwards.
Apartments remain habitable, the snack bar itself has been left unusable. Energy supplies to the building were cut as a precaution.
The intervention ended around 15:00.
"Fires linked to extraction systems in horeca establishments can spread rapidly through ducts towards roofs and façades," said Brussels fire brigade spokesperson Walter Derieuw in a statement.
