He is also the first horse to win from wider than barrier 15, and on the day, that was what made it more remarkable.
Dunaden started from the outside gate in the 18-horse field and had to give every runner a start.
With 800m to run he had only a couple behind him as Craig Williams angled to get on to the back of another French runner, Americain.
For the next 400m Williams got to work on the horse he described as "the people's champion" and as they straightened he was widest of all and running.
He then plucked off his rivals with every stride, finding the front 60m out and was the only horse still accelerating on the line.
"He is just an amazing horse," said Williams.
"When I ask him he gives me whatever I want.
"He is as good as I've ever ridden, I can't believe I've had the privilege."
An easing $14 chance, Dunaden reeled in the veteran stayer Alcopop ($16) to score by a half length.
Lights Of Heaven ($11) weaved through the field late to finish third, another three-quarters of a length away.
Americain finished fourth and the Luca Cumani-trained My Quest For Peace was fifth, giving overseas-prepared horses three of the first five placings in the A$2.5 million race.
The favourite Glencadam Gold finished 15th after leading, second favourite December Draw was 17th after racing behind the leader and Voila Ici, who also raced on the pace, ran last.
Neither Dunaden's French trainer Mikel Delzangles nor owner Sheikh Fahad al Thani of Qatar was at Caulfield.
They will, no doubt, regret it.
"Mikel came here during the week to see the horse and as soon as he did he wished he was staying," said stable representative Geoffrey Faber.
"And I know Sheikh Fahad loved it when he was here for the Melbourne Cup; he'll certainly be here in a couple of weeks."
For Williams the win went a large part of the way to compensating him for missing the winning ride on Dunaden in last year's Melbourne Cup through suspension.
The champion rider made some amends when he won on Dunaden in Hong Kong last December.
But the missed Melbourne Cup can only be made up for by another one in a little over two weeks.
"I know history says he can't do it," Williams said.
"But there's nothing this horse can't do."
Williams suggested Dunaden still had improvement to make.
As good as he is, he will probably need a lot of it after the handicapper penalises him for his Caulfield win.
Alcopop's jockey Dom Tourneur had the winning post in sight with 100m to run but had to settle for second.
But the Adelaide-based jockey could at least console himself with the fact he was beaten by "the best mile-and-a-half horse in the world".
Tourneur was travelling sweetly as the field approached the home turn, and sensing his biggest danger was poised to strike right behind him, he made a move and went for home.
Alcopop responded and charged to the lead in the straight. "Unfortunately we were beaten by the best mile-and-a-half horse in the world," the jockey said. "We put him there to win on the corner. He let down good with his light weight (52.5kg) and I made Dunaden chase with his 58kg. But he was too good."
Alcopop's trainer Jake Stephens said it was an "amazing" effort from his horse. "When he hit the front I thought, can he hang on?
"Dom had to go when he did and it was a massive run. Dunaden is a world-class horse.
"It was a phenomenal run from Alcopop and such a good thrill to see him go so well in a big race like this."
Alcopop is not entered for the Melbourne Cup so Stephens doesn't have to worry about trying to turn the tables on Dunaden.
"Off that you'd think Dunaden will be getting the double," Stephens said.
