With 10 days to go before the hosts take on Romania at the Stade de France, Deschamps sought to build team spirit after fans had whistled at Giroud and called for suspended Real Madrid forward Karim Benzema to replace him.
"It's definitely a minority (of fans) and it's obviously unfair," Deschamps told a news conference on Tuesday. "Until proven otherwise he scores goals for us which is what we ask him to do. I'm counting on him as does the team."
Giroud, who has often faced criticism at club and national level, scored a crisp volley against Cameroon as Les Bleus won 3-2 in Nantes.
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It took his tally to 15 goals in 48 internationals and he has now scored five in his last six matches for France.
Deschamps is widely expected to make him the focal point in a three-pronged attack that has notched up 10 goals in the last three games.
"Solidarity towards the players is important in a group and when you have someone like Pierre-Andre Gignac who plays in the same position defending him then that's a good thing," Deschamps said.
Benzema was not picked after a ban for his involvement in an alleged blackmail scandal was upheld by the French football federation in April.
France also take on Albania and Switzerland in Group A at the European Championship which starts on June 10.
