The defender has previously been linked with Russian giants Anzhi Makhachkala but the Stamford Bridge club are said to be pondering a bid for the 18-year-old's services.
Zouma's representatives held talks with QPR in the summer of 2012 but he remained with St Etienne, making 18 appearances for them in Ligue 1 during the 2012/13 season.
Chelsea could face competition from Bayern Munich and AC Milan for the €12m (£10m)-rated Zouma, who is currently representing France at the Under-20 World Cup in Turkey.
"If you hear of interest from Chelsea and a great manager such as Jose Mourinho, you take notice," said Zouma.
"It makes you happy, and it means you are on the right way to the top.
"I am relaxed about all the fuss about me being linked with big clubs, at the moment my focus is on the Under-20 World Cup. We have to try to win that with our generation of good young players."