Giroud started Friday night's 6-0 friendly win over Australia, scoring twice before making way at half-time for the Real Madrid man.
Benzema also netted to press his claims for a start against Finland on Tuesday.
Deschamps said he would continue to rotate the pair as he went with one central striker.
He told www.fff.fr: "Both have my trust. There are 11 players who can start. Since I became coach Karim has played more matches than Olivier.
"It is more efficient to play with a central striker, so one starts and the other comes on. We will see on Tuesday (who plays).
"In November (for the World Cup play-offs) one of the two may have problems. I want to have both, with their different qualities."
France are set to finish second behind Spain in Group I.