Giroud has insisted that both are "great keepers", but the Chelsea forward has claimed that Lloris just edges out Belgium stopper Courtois.
"They have the same right foot. They don't use it much," Giroud joked to reporters.
"Thibaut has an impressive wingspan. It's hard to beat him on the sides. He can stop balls in any area. I have scored a few goals against him in training with Chelsea and I hope I can do it on Tuesday.
"They're both great keepers. And they both deserve to be elected as best keeper of the tournament, even if I have a preference for Hugo. The best is Hugo. Sorry Thibaut."
Giroud has played 380 minutes of France's 2018 World Cup campaign, but is yet to score.