The 31-year-old Dumerc led France in scoring to win the silver medal at the 2012 London Olympics. She was selected Europe's player of the year by FIBA after the Olympics.
Dream general manager Angela Taylor says Dumerc, who signed a multiyear contract, is "one of the best point guards in the world." She is playing for Bourges Basket in France in the EuroLeague season.
The 5-foot-7 Dumerc will play for Atlanta under first-year coach Michael Cooper.
Atlanta acquired guard Matee Ajavon from Washington last month as part of a three-team trade that sent guard Alex Bentley to Connecticut.
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