Les Bleus, who drew 1-1 with England in their opening game, will need inspiration to beat the co-hosts who started their campaign with a 2-1 win over Sweden.
"I know Shevchenko well, I played against him and he was difficult to mark," Blanc, who faced Sheva wearing the Inter Milan shirt when the Ukrainian was at AC Milan, told a news conference on Thursday.
"I was not always happy at the end of the games. He is in great form, but he needs a bit of space to show it."
In Shevchenko, Ukraine have a world-class player and France must show they have at least one too, according to Blanc.
"Great players are always there on big occasions. If we have great players, they will have to prove it tomorrow because we must win," he said.
A defeat would leave France on the brink of their third consecutive first-round elimination in a major championship.
But Blanc is confident his team have what it takes to beat Ukraine who they have never lost to in six matches.
"I heard the Ukraine coach [Oleg Blokhin] said he did not fear France. He can rest assured, we do not fear Ukraine either, even if we respect them," he said.
France beat Ukraine 4-1 in Donetsk last year and Les Bleus need to prevail again.
"We came here a year ago, we beat Ukraine but the context is different. This game is not a reference but we will tell the players we can beat this team because we've done it already," Blanc said. "It will be much more difficult."
Just like Blokhin, Blanc said he did not know yet what his starting line-up would be, although he hinted Yann M'Vila could start after missing the first game through injury.
"All the players are at our disposal," he said.
"Yann M'Vila is an important player in our system. Maybe the rest he had gave him a bit of freshness and all these parametres will be taken into account as to whether he will start."
Should M'Vila be selected, Alou Diarra, who produced a solid performance against England, would drop to the bench.
"If we make changes, it will be to improve the team and not to sanction anyone," added Blanc.
Another factor will be the heat with temperatures expected to reach at least 35 degrees on Friday.
"We have to take this into account. I went to the stadium, it's an oven," Blanc said.
