It was also the second victory in three weeks for Pettersen, who carded a 3-under 68 to end at 10-under-par 203 in the weather-shortened, 54-hole French tournament.
Pettersen notched her 13th overall LPGA Tour title, finishing two shots ahead of amateur star Lydia Ko (1-under 70).
Taking sole possession of third place at minus-6 was Lexi Thompson (68), while Se Ri Pak and So Yeon Ryu (both 71s) shared fourth place one shot further back.
Second-round leader Mika Miyazato stumbled to an 8-over 79 Sunday, good for a 19th-place tie at even-par 213.
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