Benzema netted from close range from Jeremy Menez's fine run and cross early in the second half after the South American giants had been reduced in number following Hernanes' sending-off for a dangerously high challenge on the goalscorer.
After a period of decent early possession, France could easily have had a ninth minute lead. With Bacary Sagna building play from the right, the full-back cut inside to play in Yoann Gourcuff, whose first touch on the turn fell perfectly into the stride of Benzema just inside the box, but the striker fired just wide of the far bottom corner.
It was a great opportunity for Les Bleus, especially as they were left with little more than crumbs for the remainder of the first half as the Selecao showed their class.
First, Alexandre Pato bent a shot just over the bar and then Dani Alves tried to get a cross in after a rather convoluted set-piece. The home side did come close again though on the half-hour when skipper Alou Diarra got up to head a Gourcuff free-kick just over the bar.
But with the game seemingly fizzling out towards half-time, the major flashpoint arrived in the 40th minute.
With Benzema looking to get a bouncing ball under control with his chest, he was met by a ridiculously high straight-legged challenge by Hernanes which caught him in the armpit, sending him immediately to ground.
Referee Wolfgang Stark showed no hesitation in showing the red card, deciding against the normally acceptable leniency in friendly fixtures due to the violent nature of the challenge.
The numerical advantage was always likely to have some bearing, and nine minutes into the second half France took the lead.
Matchwinner | Goal-hero Benzema looked dangerous all night
Jeremy Menez ran forcefully at Elias and Andre Santos, escaped from between their grouped challenge and crossed low from the bye-line for Benzema to tap home from three yards.
The Real Madrid man could have doubled his tally within minutes when Gourcuff’s knock-down left him with a headed chance on goal, but Julio Cesar reacted superbly to keep his effort out.
Benzema had another great chance after carving through the right channel, but again Cesar saved low to keep Brazil in the match.
From the neat passing game they’d shown in the first half though, the Selecao had suddenly been reduced to chasing shadows as France began to play them at their own game in protecting their lead.
They held on comfortably to secure a result which will give Laurent Blanc’s men great confidence ahead of their Euro 2012 double-header against Luxembourg and Croatia next month, while Brazil have four months to lick their wounds before they play the Netherlands.