After Adam Ashley-Cooper's early score, France were awarded a penalty try and took a 16-13 lead courtesy of the third of Morgan Parra's three penalties at the start of the second half. At this stage, Australia's problems were largely of their own making, with their scrummaging problems being regularly exposed.
However, tries from Benn Robinson and Will Genia in the 48th and 51st minutes put Australia in control, before Mitchell claimed a quickfire hat-trick and James O'Connor added a try of his own to complete a personal haul of 29 points and the French support aired its displeasure as the final whistle sounded.
The home side's coach Marc Lievremont was stunned by the result but accepted responsibility for the second-half humiliation.
He said: "It's obviously hard to find a rational explanation for this debacle, but we played against an exceptional Australian team. However, I will take responsibility for this enormous defeat. I think I've got a quality squad that works hard and has a big margin for improvement. But it's beyond me to explain the unexplainable."
Australia more than made up for their defeat to England two weeks ago and head coach Robbie Deans said: "I think we had this coming for us for a while. Overall, despite that defeat against England, it has been a good tour for us."
Elsewhere, Mirco Bergamasco's 100 per cent accuracy with the boot saw Italy come from behind to edge Fiji 24-16 at the Stadio Braglia in Modena. The Racing Metro centre was his side's only scorer as he slotted eight penalties from as many attempts in a game which saw Fiji fade after the break.
Tuapati Talemaitoga's ninth-minute try and Seremaia Bai's kicking had inspired the visitors, but Italy's grit turned things around.