He said: "France first up is always very tough but it's the best time in the tournament to get them.
"We came fairly close in Paris last year and we are looking to try to go one better here at Murrayfield.
"Every team has got weaknesses and there is no team that is the perfect team at the moment.
"We are concentrating more on what we can do. We have looked at the set-piece area and looked at ways the French try to do things.
"But apart from that we are adopting the motto that attacking is the best form of defence.
"We will be trying not just to cope with what they do but have a go at them ourselves and try to put one over them in that way."
The 29-year-old Glasgow Warriors man is also quietly optimistic they could shock a few more nations in the championship this season.
"It's always the thing with the Six Nations," said Petrie.
"If you get a win at the start then you can really get on a roll.
"We don't want to be in a position where we have a couple of losses and the pressure is really on because we are really struggling.
"We need to start getting results right now and hopefully that will start on Sunday.
"It will be tough to win the whole tournament - as it is for everyone - and we have to go beyond our expectations.
"But it's the most open Six Nations there has been for six or more years and there's no definite winner.
"We'll be looking to go out and try to get a few good results and see where we go from there."
Petrie, who was made Scotland captain before getting injured, has also urged his team-mates to put bums back on seats.
He added: "We want to get the nation behind us as well.
"There has been disappointing ticket sales which is not very nice to see.
"But people want to come and watch rugby in Scotland if they have got something to support.
"By putting a good performance in on Sunday they will see exciting rugby is here to come and watch again.
"Hopefully then the fans will start coming back to Murrayfield in their hordes."