Harris, who launched the restaurant with Eric Garnier in 2002, closed the doors to the Brompton Road site on Friday (9 January) after selling up and resigning as director.
The chef told BigHospitality he had reluctantly sold up, but couldn't see any other choice as the area he was operating in was no longer the same.
"An awful lot of properties in Knightsbridge are owned by non-domiciles, I think something like 20 per cent of properties aren't occupied throughout the year now, so we don't have the regulars in like we used to," he said.
Harris is currently looking for a new site in London for Racine, as well as exploring other opportunities for business consultancy.
"I thought about whether to change Racine, but it works really well, so I need to be doing it somewhere else," he said.
"Opening the restaurant was the fulfilment of a lifelong ambition and this is just a step in its evolution of the restaurant until it finds a new home in 2015."
The chef is already working with others on a consultancy basis and will continue to do so until he secures a new restaurant site.
The site on Brompton Road will remain a restaurant with the Racine name set to 'remain above the door for a short duration, prior to undergoing a refurbishment'. It is not yet known how the new owners plan to develop the site.
Harris told BigHospitality staff had been offered jobs with the restaurants' new owners, but said they may move on elsewhere.
"I was particularly proud of the team I had at the end," he said, "they are so good they won't struggle to find new jobs.
"It did feel very odd not going to the kitchen this morning after 12 years, but the changes have to be made and I'm glad it allows me to do something else."
Racine became a Knightsbridge neighbourhood favourite after it opened in 2002 and picked up widespread acclaim from national restaurant critics for its famous côte de boeuf with Béarnaise sauce; veal chop and Roquefort butter and lapin à la moutarde.
Harris, formerly chef at the Fifth Floor restaurant at Harvey Nichols, left Racine briefly in 2006 to join Soho House Group. He returned two years later after buying Garnier out of his share of the business.
In a statement he said: “After 12 glorious years of serving great food and wine to a great selection of people, I have sold the restaurant and I am moving on. I want to thank our guests for all their support and enthusiasm for Racine over the years. I couldn’t have done it without the team of likeminded people, who have always shown a genuine pride to be part of the Racine family, and to whom I owe a debt of gratitude."