At about 7pm on Tuesday, 6 January, an Asian man and his two young children sat down at a table in the restaurant in Centenary Square, when a white man and woman made racially aggravated comments towards them.
The woman is believed to be in her 40s and was wearing a brown top.
The man is believed to be in his 30s and was wearing a navy blue t-shirt and jeans. He is also believed to have had a tattoo on one of his arms.
Anyone with information as to who the suspects might be is asked to contact PC Lumb at the City Area Neighbourhood Team on 101.