A man posing as a modelling agent has been charged with sexually assaulting a young woman following a fake "job interview" at a licensed premises in Sydney's CBD.

The 22-year-old woman organised to meet the 35-year-old man through an online social networking site with the intention of getting modelling work, police said.

At a licensed premises on Tankstream Way on Tuesday, the man allegedly used a false company name while pretending to represent a modelling agent, they said.

After the pair consumed a small amount of alcohol, the man took the woman to an office building on Hunter Street, where he allegedly showed her printouts of the company he claimed to represent.

He then allegedly sexually assaulted her on the floor of the office, police said.