Emma McKeon breaks down in uncontrollable tears on TV as she makes heartbreaking Olympics farewell in Paris

Emma McKeon finished her Olympic individual career with a sixth-place finish in the 100m butterfly final in Paris - and broke down in tears as she opened up about her last race at the Games.

The Australian veteran, fresh off her 4x100m freestyle relay triumph with the women's team on Saturday, had a slim chance of adding to her medal tally at the Paris Aquatics Centre, where was up against a strong field on Sunday.

And it came as no surprise when McKeon hit the wall sixth in 56.93s, with USA's Torri Huske shocking her world record holding teammate Gretchen Walsh to take the top prize.

McKeon intends to retire at the conclusion of this Olympic Games and will play a part in the upcoming medley relay swims.

She couldn't hold back her emotions as she was interviewed poolside by Aussie six-time Paralympic gold medallist Ellie Cole after the butterfly race on Monday morning, AEST.

'I tried not to think about it too much before ... Just emotional,' McKeon said through tears.

'I definitely hoped that that would've been better, but I know I've got a lot to be proud of and I think it's always going to be emotional finishing something that has brought me so much joy and so many great relationships and so many life lessons.

'I've got so many fond memories of swimming ... I just feel privileged to be here ... this is my fifth time out here already and it's only day two. I feel so lucky.'

The pool great said she hasn't had enough time to properly reflect on her career but added, 'As athletes we're always kind of looking to what the next thing is, and for me I've always been looking at how I can improve, all the time, year after year, day after day.

'So I am looking forward to the time when I can really look back on it all. I've already got so many great people around me that have already been through similar things, like my brother, who finished up swimming about three or four years ago.

'I've got a lot of people to support me.' 

While she is competing in Paris, her boyfriend Cody Simpson is not. The former pop star turned his back on swimming to pursue his dream of representing Australia at the Olympics, but failed to qualify for the Games.

The 27-year-old lavished praise on his girlfriend after her gold medal in the relay.

'We are all proud of her,' Simpson said on Nine.

'She'll be so humble about it. She'll never say it herself, but it's pretty special what she's done.

'It's unreal. She had a blistering swim this morning - she really wanted to be in that final and get on that podium.

'I'm so proud of her for getting that done.'

McKeon's victory on Saturday also saw her pass Ian Thorpe's tally of five Olympic gold medals, taking her haul to six. 

 'It's great,' Thorpe said in commentary.

'Couldn't happen to a better person, really.'

'She is the most successful swimmer, the most successful Olympian, in our country.

'She should be celebrated for the person that she is, what she's been able to deliver for the sport.'