The 22-year-old only joined the Black Cats from Turkish side Bursaspor for an undisclosed fee last month.
However, having made five appearances, the Frenchman has admitted that he is "very happy" to be a Sunderland player.
"I'm liking being here at Sunderland," he told the club's official website. "I love playing at the Stadium of Light and I love meeting the fans.
"I'm very happy here. To play in front of crowds of 40,000 is a great feeling.
"It makes me happy to be able to give them something back and sign autographs or have photographs taken."
N'Diaye has previously represented France at youth level.