The agency will support CSL in its growth plans linked to a national store expansion. An initial campaign will focus on digital, TV and radio, but evolve to include all media.
Brilliant Media Leeds was the previous incumbent on the business. The agency had picked up the account shortly after losing the £40 million broadcast DFS business to MediaCom in March last year.
However, as a result of MediaCom's acquisition of Brilliant Media in December last year, CSL started the search for a new agency.
Tracy De Groose, the managing director at Carat, commented: "CSL is redefining its sector through the use of digital performance marketing. We're extremely proud of our track record in building e-commerce business and we look forward to doing the same for CSL."