Fofana arrives at Stamford Bridge to further bolster Thomas Tuchel’s defence for the 2022/23 season, following the arrivals of Kalidou Koulibaly and Marc Cucurella earlier in the summer.
The 21-year-old signed a seven-year contract with the Blues.
On completing his signing, Fofana told Chelsea’s official website: “The two last days have been really big days for me and I’m very happy. I trained this morning with the team and it’s a dream for me. I’m very excited to start playing games for the fans and the club.
“I’m here to win trophies – the Champions League, Premier League, FA Cup, Carabao Cup, everything. I came here to win and the club is built to win trophies so I’m here to continue that.”