Belgian Thierry Neuville, the previous leader after five rounds of the world rally championship, wrecked his Hyundai in a huge crash on Saturday and was unable to continue and score points on the final day.
Ogier finished second, 23.1 seconds behind, with 45-year-old compatriot Sebastien Loeb a close third for Hyundai. It was the nine times world champion's first podium for the South Korean marque.
Tanak, who now has two wins for the season, claimed five bonus points for winning the final power stage, with Ogier second to add four to his tally.
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The Frenchman now has 122 points to Tanak's 112 and Neuville's 110. Hyundai lead the manufacturer's standings with 178 to Toyota's 149.
The next rally is in Portugal from May 30 to June 2.
World championship leader Neuville crashes out in Chile
11/05/2019 AT 17:38
Ogier and Neuville head into Monte Carlo finale seconds apart
26/01/2019 AT 16:54