It will mark the last Fed Cup final played under the current format, with an overhaul next year seeing 12 nations compete in a six-day event in Budapest.
Barty and Samantha Stosur will take pleasure in doubles for Australia in the direction of Mladenovic and Garcia.
While there will be a huge boost in prize money, it spells an end to home ties, following a similar change to the men's Davis Cup.
Mladenovic, just like Barty is fresh from her season-ending doubles crown in China with Timea Babos and is the only Frenchwomen who had an upper hand on the Australian.
"We've played in Australia every year".
France captain Julien Benneteau has kept faith with the team who sealed their semi-final win over Romania, led by Kristina Mladenovic, ranked 40 in the world.
It means Australian young guns Astra Sharma and Priscilla Hon will cheer from the sidelines, along with France's Alize Cornet, Fiona Ferro and Pauline Parmentier.More news: Clashes erupt across Bolivia amid unrest over election result
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"For all of us to be able to say that we are Fed Cup champions would be special", Barty told fedcup.com.
The enthusiastic response puts Perth on track to set a new attendance record for an Australian Fed Cup tie, with ticket sales now more than double the previous attendance record of 9,554 set in April at the Fed Cup semi-final against Belarus in Brisbane.
But Garcia doesn't believe the visitors will struggle under the conditions, saying she and Mladenovic have plenty of experience playing down under.
"That final was a great lesson for me and all of us", said Garcia, who won two singles matches in the tie.
"To be in the final again, we've already been there so we have nothing to lose", former world No.4 Garcia said.
"We have been there before, whereas the Australian girls haven't".
The omens don't bode well - Australia have lost the last eight Fed Cup finals they have contested since winning their last one in 1974.
The final is being played on hard outdoor courts at Perth Arena. "Midway through the year I wanted to make sure that I was fit and healthy and doing everything possible to be right for this weekend".