He also says West Ham is his first choice above numerous offers from abroad - and FIVE other premiership clubs.
The player is on loan from Metz and recently said he wanted to know soon where his future lay.
Well, now it appears that he does and he reveals:
"The coach told me that he personally wants me to stay here and he reassured me a little on my future on saturday by picking me, so I'm happy."
Sebastien was dropped for the Everton game and says:
"I was disappointed not to play because I want to prove to the people here that I merit a place.
"But Harry said after the Aston Villa game that he didn't regret showing confidence in me, and that's the best response I can get.
"I'm beginning to feel better and better physically and I think I'll be 100% for Derby.
"I played in a different position on saturday but it suited me better than standing alone on the touch line.
"If we continue that way it will be OK, after a really bad march which we want to forget."
Sebastien's disappointment about the recent run of results and the cup exit is tempered, however, by delight at feeling wanted at West Ham and he adds:
"The coach has told me that he, personally, wants me to stay here and he is ready to buy me so I am happy.
"I've had lots of offers from clubs, even english ones, but it's me that's going to choose and my priority is West Ham.
"They have helped me and supported me, and as I have said, the fans are so fantastic that I'd be disappointed not to stay here.
"Five english clubs are interested in me, but my agent won't give me the names in case my head is turned!
"But for my agents and me the choice is West Ham at any price and it is just a question of money between Metz and West Ham."
But what if one of the five was Manchester United?
"The main thing," he responds, "is that West Ham are in my heart, and that is important.
"I wouldn't go to another club for money.
"My wife came to West Ham and she wants to stay here, my family, and everyone at home wants me to join West Ham.
"If that isn't enough I'd be very disappointed."