The two were team-mates at Lyon, and the former PSG shot-stopper urged the Real Madrid man to make an impact against La Roja in the upcoming showdown
Benzema has so far failed to make a goalscoring contribution at the tournament, and his only input thus far has been assisting both goals for Les Bleus in the 2-0 victory over Ukraine in Group D.
Coupet, who retired after being released by Paris Saint-Germain in 2011, played with Benzema from 2005 to 2009 at Lyon, securing four consecutive Ligue 1 titles together.
The 39-year-old was France's No.1 goalkeeper at Euro 2008, a tournament in which Les Bleus finished bottom of a group containing Netherlands, Italy and Romania. Nevertheless, the goalkeeper had some encouraging words of advice for his former team-mate.
"He needs to focus and concentrate to score. Karim is a scorer. He just had a great season with Real Madrid, where he scored a lot of goals," Coupet told RMC Sport.
"Three games without scoring, it must be hell for him. All this frustration should come out and it will take a lot of heart to perform."
Kick-off at the Donbass Arena in Donetsk is scheduled for 20:45CET.