A half-century before President Barack Obama ordered a restoration of full diplomatic relations with Cuba in 2014, Jean Daniel, a French journalist on a secret mission to Havana in the autumn of 1963, delivered a proposal by President John F. Kennedy to Fidel Castro.

It was an offer to explore a rapprochement.

Despite the distrust and raw feelings of the Cuban missile crisis, which had nearly plunged the world into nuclear war a year earlier, Mr. Daniel, a confidant of political leaders in many capitals during the Cold War, found Castro surprisingly, if cautiously, receptive to Kennedy’s overture.

Three days later — it was Nov. 22, 1963 — over lunch at Castro’s seafront retreat on Varadero Beach, they were still discussing the offer when the phone rang with urgent news. Castro, the Cuban leader since 1959, picked up the receiver.

“Herido?” he said. “Muy gravemente?” (“Wounded? Very seriously?”)

Mr. Daniel — who died on Wednesday at 99 at his home in Paris, according to L’Obs, the left-leaning weekly newsmagazine he co-founded — recalled the dramatic scene with Castro in an article in The New Republic days after it happened.