The suit centers on video taken in ACORN's Baltimore office, the Associated Press reports, and seeks millions of dollars in damages from the filmmakers as well as Andrew Breitbart, who posted the video and others online. It is grounded in the notion that both parties must consent to sound recordings in the state of Maryland.
ACORN CEO Bertha Lewis has said in the past that she thanks the filmmakers, James O'Keefe and Hannah Giles, because they have "done us a good service" by finding the organization's bad apples.
ACORN fired the two employees seen in the Baltimore video.
Also Wednesday, the IRS announced that it severed ties with the group, saying it would no longer be a part of its volunteer tax assistance program. That program offered free tax advice to low- and moderate-income people, the AP reports.
ACORN, which stands for the Association of Community Organizations for Reform Now, has long been a conservative target, in part for revelations of voter registration fraud. The group came under increased criticism following the release of the videos and saw its federal funding cut off by Congress.
Powerful Democratic Rep. Barney Frank released a statement Wednesday criticizing the organization.
"The fact that people who were improperly registered to vote did not actually cast ballots in no way excuses the organization's failure to exercise better control in this way," he said. "Further, the motivation of those who went to ACORN offices and initiated the discussions involving prostitution are wholly irrelevant to the fact that ACORN's employees' actions were outrageous and further indication of an organization that is at best poorly run in many regards. The defense against sting operations is not to ban them, but to behave properly so that they do not reveal as they did in this case clear evidence of gross impropriety."