Images of three men - captured on CCTV ahead of the club's 1-1 draw with Paris St-Germain - were released on Friday.
Met Police officers said they launched the appeal in support of French police.
Chelsea FC has barred five fans from attending Stamford Bridge following the release of a video showing a black man being pushed from a Paris train.
The Wave Trauma Centre based in Belfast has said it has suspended a part-time worker following allegations that he was involved in the incident.
Amateur video shot at Paris' Richelieu-Drouot station showed a man being pushed from the Metro train while a group chanted: "We're racist, we're racist and that's the way we like it."
Chelsea has said it will ban the five suspended fans from attending Stamford Bridge for life if there is sufficient evidence of their involvement.
A spokesman said the club was writing to the victim to "apologise unreservedly", while manager Jose Mourinho has said he was "ashamed" by the alleged racism.
British Transport Police is also investigating claims of racist chanting at London's St Pancras station by men thought to be Chelsea fans returning from the Champions League match in Paris on Wednesday evening.
Superintendent Gill Murray of the BTP said an allegation of racist chanting was reported by a member of the public who was "disgusted by the behaviour of the men", who had travelled on the 18:40 service from Paris Gare du Nord.
The alleged victim of the Paris Metro incident has been identified as a 33-year-old man, known only as Souleymane S, who said the men who stopped him boarding the train "should be locked up".
Speaking to BBC Radio 5 live's Drive on Friday, he said: "I felt truly wounded to the bottom of my heart that I really couldn't believe it.
"We're in 2015, aren't we, and we're in France. We're in a civilised country and when you are in a civilised country there are certain things you can't do.
"For me, it's a humiliation. I was humiliated in my country. I was humiliated in front of my family, humiliated in front of my mother and father."
Three men being sought in connection with an incident of alleged racism by Chelsea fans on the Paris Metro have been identified, the Met Police says.