Despite losing to New Zealand and Tonga in the pool stages and only just scraping past 14-man Wales France have reached the showpiece occasion at Eden Park.
On top of that regular reports of rifts between players and coach Marc Lievremont have dogged the French throughout the tournament, while they have also clashed with the media.
"We are trying to keep ourselves in a cocoon," fly-half Parra said.
"The players are getting some negative feedback, and if some people are saying we do not deserve to be where we are then that hurts.
"We play on the pitch and we try to give the best possible image of French rugby.
"When we read the criticism in the press, we don't want to read it, but criticism from our supporters saying we do not deserve to be here or certain English or Welsh players saying the same thing, that hurts. But it brings us together."
Lievremont labelled some of his players "spoiled brats" following the 9-8 victory over Wales - with Les Bleus coach furious that they went out to celebrate after he asked them not to.
And Parra added: "Maybe he was just annoyed.
"For certain players, the World Cup has been quite difficult, and maybe they needed to go out.
"The whole group did not go out and I am not sure why he called us all 'spoiled brats'. But we have spoken about it, and that is the end of it."
Parra, who has played most of his international rugby at scrum-half, guided France to victory over Wales with his accurate goalkicking, and he is crucial for Les Bleus as they target a huge World Cup upset this weekend.
"I never thought I would be playing in the final at No.10," he said.
"It is a dream of mine, and I am trying to make the most of it and I am going to try to enjoy it the best I can, be that on the pitch or off the pitch. But for the dream to come true we have to win.
"I think when I go back to my club (Clermont Auvergne) I will go back to being number nine. But as long as I am playing and enjoying it, I don't care where I play."
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