The bank used by President Trump’s personal lawyer to wire $130,000 to a former adult-film actress flagged the transaction as suspicious and reported it to the Treasury Department, according to a person familiar with the matter.

The lawyer, Michael Cohen, wired the money to a lawyer for former actress Stephanie Clifford, known professionally as Stormy Daniels, from an account at First Republic Bank . The money was received on Oct. 27, 2016, 12 days before the presidential election, another person familiar with the matter said. It isn’t clear when First Republic reported it to the government as suspicious.

Mr. Cohen said he missed two deadlines earlier that month to make the $130,000 payment to Ms. Clifford because he couldn’t reach Mr. Trump in the hectic final days of the presidential campaign, the person said.

Ms. Clifford was owed the money in return for signing an agreement that bars her from discussing an alleged sexual encounter with Mr. Trump in 2006, people familiar the matter said.

After Mr. Trump’s victory, Mr. Cohen complained to friends that he had yet to be reimbursed for the payment to Ms. Clifford, the people said.

First Republic and the Treasury Department declined to comment. Asked for comment, Mr. Cohen offered a two-word emailed statement: “Fake News.”

Read more at the Wall Street Journal