The pornographic film actress Stephanie Clifford sued President Trump’s fixer, Michael D. Cohen, and her own former lawyer on Wednesday, making public a set of text messages discussing efforts to quash the story of her alleged affair with Mr. Trump as it emerged early this year.

The suit, filed in California State Court, accused Keith M. Davidson, the Beverly Hills lawyer who represented Ms. Clifford in 2016, of violating attorney-client privilege. It also said he withheld relevant communications from her and her current lawyer, Michael Avenatti.

The suit accused Mr. Cohen, Mr. Trump’s personal lawyer, of helping and encouraging Mr. Davidson to breach his professional duties of confidentiality and loyalty to his client this year. In 2016, Mr. Cohen paid her $130,000 shortly before the election to keep quiet about the alleged affair.

The legal challenge is at least the third that Mr. Avenatti has brought in the last three months on behalf of Ms. Clifford, known professionally as Stormy Daniels. The suit intensifies the legal pressures on Mr. Cohen, who has been a subject of Ms. Clifford’s earlier complaints, and brings Mr. Davidson directly into the fray of civil litigation for the first time.