Chelsea are banned from registering new players in the next transfer windows for their part in forcing youngster Gael Kakuta leave French side Lens, FIFA said on Thursday. Lens lodged a complaint to FIFA over the transfer of Kakuta, 18, to Chelsea in 2007, and the world governing body has made its decision accordingly. FIFA said that it's Dispute Resolution Chamber (DRC) found out that Chelsea induced Kakuta to breach his contract with Lens two years ago. Kakuta, who plays as winger for Chelsea reserves, was banned for four months and condemned to a €780,000 fine. Moreover, Chelsea will have to pay Lens a compensation of €130,000. Chelsea Response In the wake of FIFA's decision, Chelsea have issued a statement rejecting the sanctions and promising a 'strong appeal' in return. "Chelsea will mount the strongest appeal possible following the decision of FIFA's Dispute Resolution Chamber over Gael Kakuta," the statement from the London club read. "The sanctions are without precedent to this level and totally disproportionate to the alleged offence and the financial penalty imposed. "We cannot comment further until we receive the full written rationale for this extraordinarily arbitrary decision."