Djokovic, whose only previous title success at Roland Garros came two years ago, prevailed 7-6(1) 6-4 6-4 in a time of two hours and 20 minutes.
The 31-year-old was given a good test by Munar, who pushed him all the way in the first set and then more than held his own in the next two.
After sharing a break of serve apiece in the opening two games, Munar soon found himself 4-1 down as Djokovic looked to pull away.
Djokovic was pegged back in the ninth game in a set that went the distance, only to ease to a 7-1 triumph in the tie break.
The 12-time Grand Slam champion also dug deep in the second set, taking the final three games to dent his opponent's hopes, before holding serve in the final set to get over the line.