Wales eventually fell to a heartbreaking 9-8 defeat to Les Bleus at the weekend but things would have been so different had Halfpenny's long-range strike cleared the crossbar at Eden Park.
The 2009 Lion lined up a 50-metre effort with just four minutes remaining in Auckland knowing that a successful strike would hand 14-man Wales a deserved 11-9 lead and leave France chasing their first score of the second half.
Unfortunately for Halfpenny and the whole of Wales, his effort fell inches short to cut short an incredible Welsh journey in New Zealand.
"I thought the kick was there," said Halfpenny, who was one of the surprise inclusions when the Lions headed to South Africa two years ago.
"I didn't hit it quite properly, but I still thought it was going over. It wasn't the best strike, but it was on target and I will have to look at the video again to see how close it was.
"I've put in a lot of work into my kicking over the years and it all came down to that moment.
"It was not to be and it was massively disappointing. It kills me talking about it."
But while Halfpenny admits that it will take him some time to get over the events of last Saturday when referee Alain Rolland sent off skipper Sam Warburton after just 18 minutes, he believes Wales have plenty to be positive about ahead of Friday's third-place play-off with Australia and the 2015 World Cup in England.
"You cannot fault the effort of the boys. Everyone gave everything. It was an outstanding effort, but it was not to be our day," added Halfpenny.
"We are massively disappointed. We believed we could come here and win and be in the final - and we still believed it when Sam went off.
"We believed that from the very beginning. I can honestly say the boys have given absolutely everything in terms of preparation. The pain we all went through to even get on the plane was incredible. In every game the boys have given their absolute all.
"But we have to look forward. The experience the youngsters will have gained from this has been immense and I am sure it will help them in the future.
"We got this far with a young side. It is a hard pill to swallow but I am sure this experience will make every single one of us stronger.
"We can go back home and be proud to be Welsh and in four years' time I hope we can go one step further."