North Yorkshire Police said the shocking incident happened in High Petergate at 10pm on Saturday, January 27.
The woman, in her 50s, received a small cut to her knee while the man, aged in his 20s, suffered a bruise on his face, police said.
Another woman in her 20s, who was with the man and woman, did not suffer any injuries.
A police spokesperson said: "We are requesting the public’s assistance to help establish the full circumstances surrounding the incident."
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