The 21-year-old will discuss personal terms with Tottenham should he pass a medical.
N'Koudou is a France Under-21 international and has enjoyed a very good first season at Marseille after signing from Nantes just one year ago.
The winger played 41 times last season, scoring 10 goals for the French side.
The youngster tends to play on the left wing but has previously played on the right flank and also as a striker.