The 23-year-old joined Tottenham in the summer of 2015 on a five-year contract from Lyon for a fee in the region of 12million euros.
However, the winger failed to settle in England and featured just eight times in the Premier League with all of those appearances coming from the bench.
Njie’s time at Spurs was also hindered by a medial collateral ligament injury sustained in a Europa League clash against Monaco, which ruled him out for five months. The Cameroon forward did not start a single Premier League game for Spurs, making eight substitute appearances after arriving from Lyon in a deal reportedly worth more than £8 million. After returning to France he scored four times in 22 outings for OM.
Marseille took the Cameroon international on loan last season and the deal contained an option to buy for 7million euros.
Spurs have now confirmed that a permanent switch has been agreed and Njie will not be returning to north London this summer.
Tottenham tweeted: "We have reached agreement with @OM_Officiel for the permanent transfer of Clinton Njie. We wish Clinton all the best for the future."