The 29-year-old scored three times as France reached the final, but he was regularly booed by his own supporters.
"I immediately realised that the people who booed me were not anti-Giroud, but pro-Benzema," he told Le Parisien.
"It could not be otherwise. I came from a great season with Arsenal. It was just disappointing."
The Gunners striker added: "It annoyed me.
"I was not even remotely responsible for this story and I did not understand the kind of hatred that developed against me."