Last month, the Real Madrid forward was put under formal investigation after being linked to an alleged attempt to blackmail international team mate Mathieu Valbuena over a sex video and was subsequently banned indefinitely from the national team by French federation president Noel Le Graet.
Benzema's suspension could be lifted if the judge allowed him to get back in contact with the persons involved in the investigation, Le Graet hinted last Friday.
"Karim Benzema made a mistake, it's obvious," Deschamps told French daily Le Parisien of his first-choice striker, who may miss next years tournament if investigations drag on for months.
"He did not realise the situation he was in. (Le Graet's decision) is consistent, from an ethical and moral point of view," Deschamps added.
"It's a case that annoys and upsets me, I could have done without it, especially six months from the Euro. I did not see it coming."
France have been drawn in Group A along with Albania, Switzerland and Romania for the June 10-July 10 tournament.
(Reporting by Julien Pretot; Editing by John O'Brien)
