Second-half goals from Oscar, Hernanes and Lucas gave the under-fire Confederations Cup hosts a timely pre-tournament tonic in the city where coach Luiz Felipe Scolari built his reputation.
Brazil, who ended a six-match, 21-year winless run against France, had gone into the game under enormous pressure after only one win in six outings since Scolari returned for a second stint in the job last November.
While the result, if not the performance, will give Brazil some relief, France were left to face the long flight back from their brief South American tour reflecting on their fourth defeat in five matches this year and their fifth in 11 outings under Didier Deschamps.
Having rested Bayern Munich's Franck Ribery, the toothless French, beaten 1-0 by Uruguay on Wednesday, barely tested Julio Cesar as they completed their trip without scoring.
"We didn't have the head nor the legs," Deschamps told TF1 television. "We played well for 20 minutes against Uruguay and for a short period against Brazil. Even in adversity, against superior teams, we should be able to do better."
RESTLESS CROWD
Brazil's win placated a restless 51,000 crowd at the Arena Gremio, which is not among the 2014 World Cup stadiums, after they had jeered forwards Neymar and Hulk during the game.
But, with only Oscar showing any real invention and Neymar once again struggling against a European defence, it was still a far from memorable display
"The team is still being put together," Scolari, fondly remembered at Gremio where he won several trophies during the mid-1990s, told reporters. "We are working to have a competitive team that will win matches."
The teams belied their reputations as two of international football's most graceful exponents, instead setting out to concentrate on nullifying each other, producing a soporific and undignified first half.
Brazil often had four players - two central defenders plus two defensive midfielders - behind the halfway line even when they were attacking, severely limiting their creative options.
The 2014 World Cup hosts' chances mainly came from crosses into the area, which the French defence dealt with comfortably, and the occasional long-range shot which invariably went high and wide.
France occasionally looked threatening when they came forward, yet never really tested Julio Cesar.
Brazil defender David Luiz showed his wild side as he escaped a yellow card for hacking at Karim Benzema's leg near the halfway line, and was booked shortly afterwards for a needless high challenge in midfield.
The five-times world champions, who had not scored in their last three meetings against France, finally broke the deadlock in the 54th minute when Oscar produced a virtuoso finish after Fred's low cross found him in the middle of the penalty area.
France had their best chance shortly afterwards though it came from a Brazilian player when David Luiz diverted a Mathieu Valbuena cross towards his own goal, forcing an excellent save from Julio Cesar.
Scolari was jeered by the crowd when he took off Oscar in the 65th minute, yet two of his substitutes ended up on the scoresheet.
