Remy, 27, joined the Premier League powerhouse in the close-season, after spending last season on loan at Newcastle United.
The Frenchman scored 14 goals in the top flight for Newcastle, and eventually landed at Chelsea after Liverpool's initial interest in Remy faded - with reports he failed a medical at Anfield.
Remy is fighting for a spot in the XI against the likes of Diego Costa, Andre Schurrle and Didier Drogba.
And despite scoring the winner off the bench for France against Spain in Paris in their friendly on Thursday, Remy must work hard to get into Chelsea's first team - according to Deschamps.
"At the club he's just moved to, with the boss he'll have, Remy better not fall asleep," Deschamps told The Mirror, alluding to mercurial manager Jose Mourinho.
"Loic Remy needs to be more aggressive, he'll need to work hard for Mourinho."
Deschamps' comments come after he implored his squad as a whole to be "tougher", after their recent 1-1 friendly draw to Serbia.
France bypassed the Euro 2016 qualifiers, as they are hosting the tournament.
