Les Canaris went down in a penalty shoot-out against Sochaux, after the match was drawn 1-1 after extra time.
The club captain ran up to take his spot kick and tried an audacious chip down the middle of the goal only to see the ball safely saved by Teddy Richert.
Landreau could have won the cup for Nantes had he been successful from the spot, but instead his side lost when Pascal Delhommeau missed their next penalty.
Landreau insisted he was not being too cocky with his penalty and had no regrets about trying the cheeky spot kick.
"I was thinking about that for some days," said Landreau. "I have always been a player, I am and I will remain a player until the end.
"I don't regret what I did, even if in a way, I made Nantes lose.
"It was not a lack of respect. Anyway I didn't do it with that aim.
"I believe the best thing is efficiency, and I was looking for efficiency."
