A 29-year-old man required hospital treatment after he was stabbed with a syringe and beaten over the head with a bottle during a frenzied attack.
Three men set upon the victim in the capital's north inner city.
The incident unfolded outside a print store at Sackville Place at around 11pm on Sunday when the man, who had earlier been out socialising, walked past three homeless men who had been sleeping rough there.
One of the men asked the person walking by for a cigarette but when he told them that he did not have one, a black-haired male produced a syringe and threatened the man who was forced to hand over his mobile phone and a quantity of cash, believed to be less than €100.
According to the account given to gardai by the victim, he then punched the homeless man who had threatened him with the syringe.
But after this, the three homeless men set upon the man who has an address in the Clonsilla area of west Dublin. He was beaten over the head with a bottle and stabbed with a syringe as well as being punched and kicked.
After the vicious assault, it is understood that the three men escaped in the direction of North Earl Street.
Emergency services were notified and the man was rushed to the Mater Hospital where he was treated for non-life threatening injuries.
Meanwhile, shortly after his attackers fled, sleeping bags and cardboard boxes owned by the homeless men were set on fire.
The massive blaze caused severe damage to the shutters and windows of the Aungier Print store at Sackville Place - a location in which homeless people have been sleeping outside for some time.
When contacted by the Herald, an employee of the shop said: "What has been going on around here has been crazy and it has been like that for years now.
"There is major problem with homeless people and anti-social behaviour in this part of the city."
The case is being investigated by gardai at Store Street Station and no arrests have yet been made.