The 23-year-old Cameroon international joined from Monaco last summer and has been a regular starter for the Ligue 1 side, although he is currently out with a hamstring problem.
Full-back N'Koulou is the reported target of Premier League clubs Arsenal, Tottenham and Liverpool as well as a whole host of other European clubs.
And he told Sky Sports: "The club and me are together on my future. If they receive an offer they can't refuse, then we will have to part company.
"Marseille is a great club and I love playing for them. They are part of my life."