Juan Carlos Vera filed the suit against James O'Keefe and Hannah Giles, alleging they violated a state law prohibiting the recording of conversations without the consent of all participants, The San Diego Union-Tribune reported Wednesday.
O'Keefe and Giles visited the ACORN office in August 2009, and made audio and video recordings of a conversation with Vera purportedly showing Vera discussing using housing loans to set up a prostitution ring, the newspaper said.
The national community-organizing group, which held voter registration drives and assisted poor people with housing and other issues, has since disbanded.
The tapes, released on the Internet, had been heavily edited, according to an investigation by the state attorney general's office.
Footage was added of O'Keefe and Giles dressed as a pimp and prostitute to make it appear they were dressed that way in talking to Vera, when actually they were not.
The investigation found no wrongdoing by ACORN employees and said Vera had reported details of the conversation he had with O'Keefe and Giles to police.
The report strongly implied O'Keefe and Giles had violated state privacy laws, but they were granted immunity in exchange for providing the unedited tapes, the Union-Tribune reported.