The 22-year-old had previously been the interest of several European clubs, but insists he wants to remain at Stade Velodrome for now
The Cameroon international moved to Stade Velodrome from Monaco last summer, and despite the club's indifferent form, N'Koulou enjoyed a good individual debut season.
With the talented stopper reportedly being tracked by the likes of Arsenal, AC Milan and Barcelona, N'Koulou insists that he remains "very attached" to L'OM.
"As a player, it is a pleasure and a sense of pride knowing that you can please the biggest clubs," the centre-back told the club's official website.
"But we must calm down and not be lulled just because it says here and there. The key is to work and progress. I am very attached to OM.
"I cannot see myself leave the club this season. Knowing its history and its record, it is important for me to be here."
Marseille travel to Reims in their first Ligue 1 game of the season on Sunday. Kick-off is at 21:00 CET.