Les Bleus were just 12-9 ahead with 13 minutes to go before Gael Fickou, Baptiste Serin and Jefferson Poirot dotted down to secure victory against the underdogs.
It was the type of inconsistent performance followers of French rugby have seen all too frequently – breathtaking flair let down by a raft of handling errors.
But the bonus point keeps the pressure up on old enemy England, who play Argentina on Saturday in another Pool C clash of the heavyweights.
France looked sharp at the outset, an incisive break by fly-half Camille Lopez slicing open the United States midfield after just two minutes.
And Les Bleus were on the scoreboard four minutes later, a counter-attacking move ending in a sublime Lopez chip for winger Yoann Huget to dot down for a scintillating try.
USA coach Gary Gold had called on his team to improve “every aspect” of their game after they went down to England 45-7 and the Eagles held their own for the first quarter, as AJ MacGinty scored a penalty after some pressure on the French line. (AFP)