The midfielder is enjoying career best form this season.
"I came to Chelsea at the age of 12, as their scouts spotted me in a small Marseille club," he told La Gazzetta dello Sport magazine SportWeek.
“It was very tough, those first two years, going from the seaside of Marseille to the fog of London. The food was a serious problem too, as I went from having cereal to breakfast to a plate of eggs and bacon. It was impossible to digest.
“My teammates in the Chelsea youth team were Tammy Abraham, who is now the centre-forward of the senior squad, Ruben Loftus-Cheek, Charly Musonda… we won the UEFA Youth League and the U21 Premier League.
“Every now and then, I wonder if I should've waited longer for my chance at Chelsea, but I had to play regularly and I was behind Hazard, Pedro and Willian in the pecking order. It's not that they were better than me, but they were ahead in the hierarchy.