A win over Albania and a 1-1 draw with Romania have put the Swiss in second spot ahead of their meeting with the host nation in Lille, and a victory would see them pip Didier Deschamps' side to top spot.
France, meanwhile, have already sealed their place in the last 16 with two wins from two and need only avoid defeat to safeguard first place.
Les Bleus captain Hugo Lloris has called for his side to justify their place as favourites by beating Switzerland - just as they did at the World Cup two years ago - but Petkovic has challenged his own players to show they have the same level of quality as their opponents.
"France are still favourites for the group and for the competition," he said on Saturday.
"In the first two matches we've seen their ability but it's not always easy. We can see how much pressure there has been from the media and French television. They've done well in results and their play, just like all top sides at major tournaments, they improve one game after the next.
"Tomorrow we'll face a great side but we want to show that we're equally great.
"We'll try to play our football and cause problems for France but it doesn't only depend on us. We'll have a chance and we want to make the most of securing top spot, which is prestigious and perhaps gives you an easier opponent on paper in the next round."
Granit Xhaka, who has twice taken the man-of-the-match awards for Switzerland so far in these finals, is looking forward to facing new Arsenal team-mates Olivier Giroud and Laurent Koscielny on Sunday, though he says club allegiances mean little at present.
"I'm happy to face my team-mates but it's not so important tomorrow," he said. "They represent France and I play for Switzerland. It's a lot more important than Arsenal now.
"You can see that so-called small teams don't exist anymore. They try everything to play, even in the area. We'll see that tomorrow as well.
"France are favourites for the whole tournament and if you can cause such opposition problems then it can have an influence on our tournament. But they have outstanding qualities and everything has to be right for us tomorrow."
Switzerland captain Stephan Lichtsteiner spent three years with Lille in Ligue 1 before joining Lazio in 2008, and Petkovic expects the experienced full-back to deliver a top performance in front of some old fans.
"He's an important player, he has a significant role within the squad," he said. "I think his homecoming tomorrow will let him prove great things to the city again. Lots of people here are very fond of him."