France's tournament came to an end on Friday as they lost their quarter-final to Germany 1-0 in Rio de Janeiro but Landreau reckons Didier Deschamps' men have shown enough in Brazil to indicate they are heading back towards the top of world football.
After a disgraceful World Cup campaign in South Africa four years ago, which was plagued by infighting, France rebuilt their team and arrived in Brazil with the third-lowest tally of caps across their squad (ahead of only Algeria and Australia).
Landreau is convinced France learnt a lot at the World Cup and will be ready to challenge for the title when they host the European Championships in two years.
"There's been a big investment in terms of work, the squad and on a human level, which is why the feeling right now is one of frustration and disappointment," Landreau told FIFA.com.
"If you look at our performance and the image we've projected, though, I think that this World Cup has been very positive and important for the France team and our country. Something has happened here in Brazil, and the team's only going to get stronger.
"We've got Euro 2016 coming, and the experience we've picked up here is going to stand us in good stead."
Landreau, who holds the Ligue 1 appearance record with 795 games to his name in the French top flight, announced in May that he would retire once France's World Cup campaign was over.
The 35-year-old goalkeeper, who did not add to his 11 French caps in Brazil, conceded it was a tough way to finish his career, after watching his team lose at the Maracana.
"It was a strange afternoon. It was tough, frustrating, and obviously I'm never going to forget it," he said.
"We had our moments during the game, but we're still a very young team."
Landreau was thrilled, however, to finish his career watching Manuel Neuer produce one of the performances of the tournament as Germany's goalkeeper kept France at bay.
"Finishing off at the Maracana, against him, at a time when he's at his peak, is like fate smiling on me," the veteran said.
"I've played a few matches against him and I saw him make his debut. And tonight he went and asked me for my jersey. I have to say I was moved."
