The accused, Furqan Ahmed (28), allegedly made some obscene and vulgar gestures when the woman came to the AAP legislator's office to discuss about a notice she had received from the civic body in connection with some construction and the MLA was not there, said a police officer.
When the complainant objected, the accused allegedly threatened her.
The complainant ultimately narrated her ordeal to her family members and later approached the police.
Ahmed is the brother of Imran Hussain, legislator from Ballimaran and Delhi's minister for environment and food and civil supplies.