Latvala started the day with a cushion of 8.2s, but immediately added to that by taking 2.6s out of Mikkelsen on the opening stage of the second day.
The Finn stretched his lead again on the following two stages, Mikkelsen losing 3.2s to Latvala on the following test before conceding another 0.7s on the third stage of the loop to fall 14.1s adrift of the rally leader.
Mikkelsen has strengthened his grip on the runner-up spot, his lead over Citroen's Kris Meeke in third growing from 23.1s to 46.5s during the trio of stages.
France Rally
Latvala closes on Rally of France win
05/10/2014 AT 08:00
Meeke however insists his focus is now on securing another podium finish, the Briton maintaining an advantage over Hyundai driver Dani Sordo of just over 30 seconds.
Sordo finds himself coming under increasing pressure from M-Sport Ford man Robert Kubica, who overhauled both team-mate Mikko Hirvonen and Citroen's Mads Ostberg during the morning loop with some impressive stage times.
Elfyn Evans managed to drag himself back up to joint eighth place alongside Bryan Bouffier after his electrical failure yesterday, while Thierry Neuville also crept into the top 10 for the first time since suffering turbo problems on Friday.
Sebastien Ogier remains over five minutes away from the point-paying positions, and will be looking to Sunday morning's powerstage finale to ensure he does not come away from his home rally empty-handed.
France Rally
Latvala extends lead in France
03/10/2014 AT 15:07
France Rally
Latvala tops France shakedown
02/10/2014 AT 14:45