Attorney General Martha Coakley is suing Lawrence Mayor William Lantigua for failing to file campaign finance reports.
The lawsuit filed Wednesday in Suffolk Superior Court asks that Lantigua be ordered to submit his 2011 year-end campaign finance report with the state Office of Campaign and Political Finance.
Campaign finance reports include details about who contributed to a candidate's campaign and how the money was spent.
The lawsuit also seeks an order compelling Lantigua to personally pay any penalty imposed by the campaign finance office instead of using funds from his political committee.
Coakley said the penalty remains unpaid and has now reached the statutory maximum of $5,000. The 2011 report was due nearly a year ago.
A call to Lantigua's office was not immediately returned.
Lantigua recently announced re-election plans.