On a thrilling final day of action in La Defense Arena, the American women turned on the afterburners to lower their own 4x100m medley relay world best while China powered to the men's title.
It concluded an electric nine-day meet marred at the start by a lingering Chinese doping scandal but which was overtaken by some outstanding individual performances.
Once again the United States topped the overall medal table with 28 ahead of Australia's 18. China came third with 12.
Their two titles on Sunday meant the Americans finished with eight gold to Australia's seven to keep intact a record they have held since 1988.
With the crowd urging him on, defending champion Finke powered home in 14min 30.67sec to better the previous best of 14:31.02 set by China's Sun Yang at London in 2012.
Italian Gregorio Paltrinieri took silver and Ireland's Daniel Wiffen, the 800m winner, bronze.
"I had a pretty decent lead at about the 300 and I knew I had to keep going," said Finke, who led from the onset and was never seriously threatened.
"Hopefully try to make the guys hurt a bit trying to catch up with me.
"They started catching up with me and I started to get a little worried, but I decided to keep pushing and as long I could keep a little bit of a distance I knew I was in a good shape for the race."
Asked if the world record was a target going into the race, he replied: "No."
"I could see the world record line on the board a couple of times," he added. "It wasn't like I was trying to see it. I just happened to see it."
Sjoestroem, 30, thundered to the wall in 23.71 to be crowned 50m freestyle champion ahead of Australia's Meg Harris and China's Zhang Yufei.
It was only her third career Olympic gold medal, compared to the 14 she has won at world championships.
But she was always the favourite, winning the last three world titles after finishing second in Tokyo to Australia's Emma McKeon who did not qualify for the event in Paris.
Career peak
The world record holder, Sjoestroem has swum the six fastest times in history, including the third quickest in the semi-finals to fire a warning shot.
"Well, this was definitely my best one with the two golds. I never thought I would win the two goals on my fifth Olympics," she said.
"It's unbelievable. I can definitely say, I'm not gonna be better than this. Like this is the peak of my career for sure."
But Sjoestroem said she had no plans to retire.
"I'm definitely going to continue swimming for many years, but I mean, how can I top this ever?"
She is also the world record holder over 100m, a title she won in Paris by beating American Torri Huske and Hong Kong's Siobhan Haughey.
The American women -- Regan Smith, Lilly King, Gretchen Walsh and Huske -- were untouchable in the medley relay, storming to a world best 3:49.63.
It lowered their previous record of 3:50.40 set in 2019, with Australia taking silver and China bronze.
Chinese 100m freestyle world record holder Pan Zhanle swam a blistering final leg to hand his country gold in the men's medley ahead of the United States and France.
The team of Xu Jiayu, Qin Haiyang, Sun Jiajun and Pan touched in 3:27.46.
