Chelsea had a representative in the stands for Marseille’s 3-0 defeat to Lyon on Sunday, according to reports in France.
The Blues are not able to sign any players this summer due to a transfer ban, but they are believed to be keeping an eye on Marseille defender Boubacar Kamara.
The 19-year-old’s contract at the Ligue One club expires in 2020, and Chelsea would be free to talk with the player in January ahead of a possible switch next summer.
Kamara only made his senior debut in the 2016/17 season, playing as a right-back in the French League Cup defeat to Sochaux.
He has subsequently played as a holding midfielder and a left back, but manager Rudi Garcia made him a permanent fixture at centre-half at the beginning of this season.
Kamara has made 35 appearances in all competitions this campaign, scoring one goal. However, his side have missed out on the Champions League places, having fallen seven points behind the top four with two games to go.