Chelsea is forced to pay 20 million euro, equivalent to approximately 236 million kronor, while Barcelona will be fined 15 million euro, approximately 177 million kronor.
The two major clubs also risk further fines in coming seasons if they do not meet Uefa's economic requirements.
Chelsea has been examined for an internal sale of two hotels within the club's own parent company, Blueco 22, where the deal amounted to over 1 billion kronor.
Chelsea's fine is equivalent to the record penalty of 20 million euro that Uefa handed out in 2014 to Manchester City and Paris Saint-Germain. They were the first penalties under the then new system with financial fair play.
French Lyon is also penalized. The club will be fined 12.5 million euro, approximately 147 million kronor.
