The paper started printing correspondence Caillaux had sent to his wife, Henriette. Digging up private love letters is never very classy, and Caillaux had written these when he was still married to another woman, with Henriette his mistress. The letters didn't exactly reveal Caillaux had been having an affair, but they certainly dropped a few hints, and who knew what further, more explicit letters they had in their arsenal. So, Henriette made an appointment to meet the paper's editor, Gaston Calmette, presumably to entreat with him personally to publish no more of them.
Turns out Henriette Caillaux had more on her mind than measured negotiations. She hid an automatic pistol in her furs as she made her way into the editor's office. The man wasn't available immediately, so she went away for an hour, came back, was admitted to the office, greeted Calmette ... and then shot him six times. She hung around the office as doctors and the police came, but she refused to let the police take her to jail. "Je suis une dame!" she said, so she insisted that her personal chauffeur take her to jail.
Calmette died, and Henriette went on trial. But after a week of testimony, the jury took an hour and acquitted her. Henriette had killed the man due to "unbridled female passions," her lawyer argued, and the jury agreed it had been a crime of passion — a phrase that normally refers to crimes that are not premeditated, but the jury apparently took the phrase in this case to mean "crime that is related to sex in some manner." And as big a deal as an editor's murder may seem, people soon had other concerns. Just hours after the verdict, World War I was declared.
During this war, incidentally, Caillaux got a little too cozy with German agents, so though Henriette got off, Caillaux was very much found guilty .. of treason. And speaking of collaboration with Germans...