France's Leon Marchand added two more golds to his personal Paris Games medal haul on Wednesday as he wrote his name into Olympic Games history.

Marchand overtook Hungary's Kristof Milak in the closing stages to grab gold in the 200m butterfly before powering to victory in the 200m breaststroke final less than two hours later.

In doing so, the 22-year-old became the first swimmer to win both events at the same Games.

"I've fulfilled a lot of dreams since I've been here," Marchand said. "Doing this double was something I felt I could do. But to really do it, that's something else."

"Of course, I had a lot of doubts. Because everyone told me it wasn't possible."

Marchand now has three gold medals at these Games, having also clinched the 400m individual medley crown on Sunday.

He will aim for a fourth gold in the 200m individual medley on Thursday.

"I'm just trying to keep going. I really enjoyed every moment of those two finals. It was really amazing for me to swim those," he said.

"The 200 butterfly was crazy. I had a really good race strategy. I managed to stay fairly close to the favorite and I really managed to catch him...with the pool on fire. It was pretty crazy to experience that as a French swimmer. I'm so happy.

"Now I'm going to have to realize what happened, appreciate every moment - and above all, refocus for the 200 individual medley."