The blaze erupted at a restaurant on Nguyen Thien Thuat Street at around 7 am, prompting firefighters to dispatch two engines and dozens of personnel to the scene.
Authorities said the five people had already escaped safely before firefighters arrived.
As the fire burned inside the building and the exterior was sealed by a roller shutter, firefighters used specialised equipment to force entry before extinguishing the blaze within about 10 minutes.
No significant property damage was reported.
Preliminary investigations suggest the fire may have been caused by an electrical short circuit.
