Mallory Swanson scored the only goal of the match in the 57th minute to help the Americans secure their record fifth Olympic title.
Three of them have come at the expense of the Brazilians, whom the Americans also beat in the 2004 and 2008 finals.
Saturday’s game also marked the probable farewell from international play of Brazil’s Marta, the six-time FIFA player of the year. She entered the game in the 60th minute but could not summon her old magic.
The Americans thrived in France under new coach Emma Hayes, who took over a squad undergoing transition after the retirement last year of longtime star Megan Rapinoe.
