The former Arsenal and Barcelona attacker, who won World Cup 1998 and Euro 2000 in a 123-cap Les Bleus career, also acknowledged that Portugal captain Cristiano Ronaldo is almost impossible to subdue for a full match.
However, Henry thinks the feel-good factor and team spirit in France's camp will be enough to get his nation over the line.
"Portugal can make the game ugly - they know how to play like that," Henry, France's record goalscorer, told BBC Sport .
"Wales did a good job against Ronaldo. He was nowhere to be seen - and then 1-0. It looked like he was getting annoyed, but how do you stop that?
"You know in the game he will have chances. Sometimes you have players who need to grow into the game, get the rhythm. Ronaldo can be anonymous, lose a lot of balls, but he still knows that he can score. He stays focused.
"I played with striker David Trezeguet, who was outstanding at that. He might not touch the ball all game but he could score a goal.
"When we are at home and we want to do something together, with all the diversity we have we are hard to beat. There is definitely something happening. Now for the last hurdle: Ronaldo and Portugal.
"We won the Euros in 1984 and 16 years later in 2000. Now it is 16 years later from then. We have a habit of winning tournaments at home. There is something about our culture.
"Six years ago everyone was laughing at us. Now we need that cup at the end to show how far we have come."
Henry also hailed the leadership of head coach Didier Deschamps and praised his former team-mate for learning from his mistakes.
He continued: "When you have a guy who has won battles before as a leader, you are going to follow him, simple as that.
"He made some mistakes through the group stage - but he wasn't afraid to change at half-time, to leave players on the bench. He has a winning mentality. On top of everything, when he gives you the plan and it works, you follow that guy until you die. Hopefully we can then win the war.
"If you have a plan, a philosophy and a leader, you can be calm when things are going wrong. There is security in the group. It helps when you win."