Gaur claims that a photograph of her was flashed in a scene where Emraan Hashmi's character is shown images of missing prostitutes, according to Mid Day.
She told the paper: "How can they use my photograph in their movie just like that? There was no contract, nothing at all. Just using my photograph for a scene like that is not acceptable to me."
Gaur added that she was worried using a picture of her to show a prostitute could affect her career prospects.
However, the Bhatts have said that they received permission from a model agency to use the photographs of the company's clients.
Mahesh commented: "You've seen the film, you'll understand that it's not our intention to malign, demean or tarnish the image of the people whose photographs feature along with that of Yana Gupta, whom the scene zeroes on."
He insisted that the Bhatts are unlikely to let the matter go to court because of the expense.
Murder 2 is an erotic thriller which follows a Goan ex-policeman, played by Hashmi, who decides to investigate the disappearances of local prostitutes.
The Bhatts are planning to turn the films into a franchise with Hashmi staying in the lead role.
Watch the trailer for Murder 2 below: