London's Metropolitan Police has said it is taking the Paris Metro incident "very seriously".
In a statement it said it would assist the French authorities to identify the people involved and support them in any action they chose to take.
Chelsea FC said it would help police, and any fans involved faced a ban.
A spokesman for the club said the fans' actions had "no place in football or society".
Link BBC News - Paris Metro racist abuse victim calls for Chelsea fans' punishment
In a statement it said it would assist the French authorities to identify the people involved and support them in any action they chose to take.
Chelsea FC said it would help police, and any fans involved faced a ban.
A spokesman for the club said the fans' actions had "no place in football or society".
Link BBC News - Paris Metro racist abuse victim calls for Chelsea fans' punishment