[4] Having started his professional career with Caen in the 1998–99 season, Mendy moved to Paris Saint-Germain in 2000 where his eight-year was only interrupted by a season-long loan at Bolton Wanderers.

Even though he had impressed a lot of people with his qualities during his first two seasons at PSG, he was loaned to Bolton Wanderers of England for a year, where he was appreciated for his offensive and speedy style.

In 2008, he came on as a substitute and scored the decisive goal in the final of the Coupe de la Ligue against RC Lens in a 2–1 victory, calmly stroking the ball home from the penalty spot.

[8][9] Mendy had stated his desire to return to England, to play for his favourite football club, Manchester United.

[10] Instead, on 20 June 2008, it was reported by BBC Radio Humberside that Hull City had offered Mendy a three-year deal to join the newly promoted English club.

[12] On 25 June 2012, Mendy returned to playing in the French league by signing a two-year contract for Stade Brestois on a free transfer.