Five fire brigade units and one ambulance were called to a fire on Gardiner Street on Wednesday morning.
The fire broke out in a four-storey Georgian building in the city centre and emergency services were called to tackle the blaze at 6:40am.
Shortly after 7am the blaze was put out, and there were no initial reported injuries.
A spokesman for the Dublin Fire Brigade said "it is still an ongoing incident."
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Three fire crews are remaining at the scene to vent the building and secure the scene.
The incident lead to some traffic delays near Gardiner Street for motorists driving into the city centre from the northside this morning.