Authorities say the victim, a 33-year-old man, was asking for the autograph outside the Mark Hotel around 2:15 a.m.
She declined, but he apparently kept pushing closer. Two members of her entourage then intervened.
Video obtained by TMZ shows one of the men pushing the victim to the ground while another kicked him in the head.
Police say three men fled the scene.
The victim, identified as Giovanni Arnold, was taken to New York-Presbyterian Hospital, where he was treated and released.
Arnold is a known autograph broker who has gotten autographs from Cardi B and countless other celebrities in the past and is even currently selling some of her autographs on his website. He is alleging that the rapper Offset directed three members of their entourage to attack him.
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He has retained attorney Daniel Szalkiewicz, who issued the following statement --
"This was an unjustified ambush by rabid members of Offset and Cardi B.'s entourage. Our client was beaten to a pulp for requesting an autograph. Our client was held in the hospital overnight for observation. The videos clearly show this was not an act of self defense. The assailants fled the scene to avoid being arrested for their savage attack. There is no doubt in my mind the NYPD will be able to track these criminals down and bring them to justice. No fan should ever be treated in this manner and words never justify violence."
Police are looking to talk to the two members who were allegedly involved in the assault.