The 25-year-old has scored just three goals in his last 28 appearances for les Bleus, and was on the receiving end of jeers from the Real Madrid faithful during their win over Getafe last weekend.
"He knows what I expect of him and he realises that he can do more," he told Radio Francia Internacional.
"The problem with Benzema is that he has been inefficient for a long time. He says that he is not affected [by the abuse], but he gives the impression of a player who is not well."
Deschamps accepts the striker may be suffering from a a lack of confidence, but believes a stroke of good luck could be enough to help him out of his current plight - something which, he says, affects the very best players.
"We speak of a lack of confidence and sometimes it takes a bit of luck too, because sometimes an opposition goalkeeper will make great saves," Deschamps added.
"What differentiates the best attackers from the others is their effectiveness, but even so, they have all been through tough times as well."
Benzema joined Madrid from Olympique Lyonnais in 2009, and has scored 91 goals in 189 appearances for the club.
At international level, he has represented France 60 times, scoring on 15 occasions since his debut in 2007.