No formal offer has been made by Chelsea for Gusto, but he has already agreed personal terms with the club on a six-and-a-half year deal and wants to move to Stamford Bridge.
Lyon will try to take the 19-year-old back on loan until the end of the season. However, Chelsea are reluctant to agree and want him to join them in January.
A product of the Lyon academy, Gusto, who has also been linked with Manchester United, made his debut for the club aged 17 and has already made 47 senior appearances for the first-team.
He is also on Didier Deschamps' radar for the national team having represented France at every age level apart from the men's senior side.
An attacking full-back with great pace and crossing ability, Gusto has around 18 months left on his existing Lyon contract.