N'Koudou signed for Marseille a year ago from Nantes for just £1m and Spurs are set to pay around £10m over the price his current club payed after having a successful first season at Marseille.
The 21-year-old winger scored 10 goals in 41 games for the French side and has also mades six appearances for France's U-21 team.
Clinton N'Jie signed for Spurs last summer from Lyon, but had a disappointing first season at White Hart Lane, failing to score in 14 outings for the north London club.
Marseille will sign the striker on a season-long loan with a view to making the deal permanent for a fee of €7m. The 22-year-old will hope to get his career back on track in his season at Marseille after losing his way at Spurs.