Emergency services were called to Eccleston House, Aiken Street, just after 6am
Avon Fire & Rescue Service have confirmed the fire was started deliberately.
This afternoon a man was arrested on suspicion of arson with intent to endanger life.
A spokesperson for Avon & Somerset Police said:
“We’re grateful to the community for their support for the displaced residents, with rest centres at Tawfiq Masjid and Centre and St Patrick’s Catholic Church. Bristol City Council-led teams are working to help residents with welfare, care and accommodation needs”
Enquiries continue. Anyone with information which could help the police investigation is asked to call 101 and give the reference 5222252558