The Brussels fire brigade responded to a fully developed fire on the first floor of a two-storey house with an attic on Van Bortonne Street in Jette district on Monday at around 1.50 p.m.
Two police officers and a couple with a child were hospitalised for smoke inhalation, according to the fire service.
Firefighters attempted to extinguish the blaze from the outside before tackling it from within. Their prompt action prevented it from spreading to neighbouring houses.
Flats on the ground floor and at the rear of the building were untouched, but the upper floors are now uninhabitable.
The cause of the fire has yet to be determined.
