PARIS — The world economy is moving into a self-sustaining recovery, but high unemployment remains a threat three years after the financial crisis, a prominent economic research organization said Wednesday.

“The global recovery is getting stronger, more broad-based, more self-sustained,” Pier Carlo Padoan, the chief economist at the Organization for Economic Cooperation and Development, said.

“The private sector is driving growth,” he added, “especially through a pick-up in trade,” while at the same time, support through government spending programs “is being withdrawn slowly.”

The O.E.C.D. represents 34 leading developed economies, including the United States and the other members of the Group of 7 industrialized nations. The Paris-based organization is marking its 50th anniversary this week, with the celebration timed to overlap with a Group of 8 summit meeting taking place in Deauville, France, on Thursday and Friday.