With EWS world champion Jared Graves sidelined with a shoulder injury, Clementz held the lead consistently by riding smart, not pushing too hard and staying on his bike, finishing ahead of rival Fabien Barel.
New Zealand downhill rider Wyn Masters turned in an impressive third place finish in his first EWS race, a stunning result for a racer from outside the discipline.
New Zealand riders had a strong presence with three riders in the top 10, including Masters, fourth-place finisher Justin Leov and Matt Walker in seventh.
For the women, Chausson said it was a long day and a hard race, which simply challenged riders to stay on the bike.
"I'm really really happy. It's the first race of the season, so it's better to start the season with a win, I'm stoked." Tracey Moseley, the 2014 Enduro World Series winner, finished second.
The Giant Toa Enduro at Crankworx launched from Te Puia's Pohutu Geyser.
-Results. Men: 1. Jerome Clementz (Fra) 35:20.46, 2. Fabien Barel (Fra) 35:33.19, 3. Wyn Masters (NZ) 35:35.67; Women: 1. Anne-Caroline Chausson (Fra) 41:20.94, 2. Tracy Moseley (GBR) 41:35.23, 3. Cecile Ravanel (Fra) 42:39.78.