Periault and Duffy were running shoulder to shoulder but the Frenchwoman pulled away from the Bermudan on the third lap of the run.
Valerie Adams chalks up another medal for the mums.
Images from Saturday's proceedings at the World Athletics Championships in Doha.
A summary of Thursday's events at the World Athletics Championships.
In other India-related news, Manish Kaurav (KL3 men 200m) and Manjeet Singh (VL2 men 200m) made it to the finals of their respective events for the first time in the history of the tournament.
Images from the World Athletics Championships in Eugene, Oregon, on Saturday, Day 9.
Summary of sports events and persons who made news on Thursday
Hansle Parchment of Jamaica was second in 13.03 and Olympic champion and world record holder Aries Merritt claimed bronze in 13.04 seconds.
Images from the World Athletics Championships in Eugene, Oregon, on Friday, Day 8.
A round-up of results from the final day of the World Athletics Championships in Doha on Sunday
Drysdale wins close single sculls gold Also, check out late gold medal winners from Day 7...
American Noah Lyles shot to 200 meters world championships gold on Tuesday, providing a bright finish to a day darkened by yet another doping scandal.
A summary of sports events and persons who made news on Friday.
Dina Asher-Smith seized her golden opportunity to win the World Championship 200 metres on Wednesday and become the first British woman to claim a global sprint title.