Midfielder Yohan Cabaye and right back Mathieu Debuchy, both Newcastle players, added the other goals.
"They move the ball so well and spread the game that it became really difficult for us," Australia coach Holger Osieck said. "We lost by a big margin, but you also have to consider the quality of the French team."
After Giroud missed a good chance when being set up by Ribery the Arsenal striker shot straight at goalkeeper Mitch Langerak France scored a penalty when David Carney was judged to have handled the ball from Ribery's cross.
Ribery netted his 15th international goal with a rising shot over Langerak, who guessed to the right.
Giroud got his first of the night eight minutes later.
He was off balance and the ball was slightly behind him when he received Ribery's pass, but he showed great technique to delicately clip a curling shot over Langerak's head for his fourth international goal.
He got his fifth 10 minutes later, neatly side-footing the ball past Langerak after Ribery and Nasri had carved open Australia's defense with one-touch passing and Nasri pulled the ball back perfectly from the left.
Australia was in total disarray as France poured forward in a blur of pass and move that must have had Deschamps smiling from the sidelines and Cabaye made it 4-0 with only 30 minutes played.
"We made the game easy because we were efficient and created chances," France coach Didier Deschamps said. "We played with a lot of fluidity. We put them under pressure all the time."
This time, Nasri played Ribery into space and he showed great awareness to pick out Cabaye's late run to the edge of the area. Cabaye did not even break stride as he struck a superb shot into the bottom corner.
Benzema replaced Giroud at the start of the second half.
France took only three minutes to score again, with Ribery's cross poorly cleared by the defense and landing at the feet of Debuchy, who hit a crisp shot into the left corner for his second international goal.
Benzema pounced four minutes later and applauded the crowd as they chanted his name.
"I'm pleased for him," Deschamps said. "He needed it."
He should have scored another midway through the half but Loic Remy scuffed a shot wide rather than pass across goal to give Benzema a tap-in. Benzema, having waited for so long to score, was understandably furious.
So should Osieck be.
Since qualifying for the World Cup, Australia has lost four and drawn one of its five games, conceding 19 goals including a 6-0 thrashing by Brazil in the previous game.
"When you concede it's not always a matter for the defenders, it's the entire team," Osieck said.
It could have been more, but Langerak made fine saves to deny Nasri and Moussa Sissoko late on.