Chelsea say Fifa treated them more harshly than Manchester City despite their transfer ban being cut on appeal.
The Blues’ two-window ban was halved by the Court of Arbitration for Sport, freeing them to buy players next month.
City did not get a transfer ban after they were also found to have broken rules on signing young players.
“Fifa chose to treat Chelsea entirely differently to Manchester City for reasons that make absolutely no sense,” read a Chelsea statement.
“The approach taken by Fifa to this case has been deeply unsatisfactory.”
Fifa accused Chelsea of breaching rules on the signing of 27 under-18 players. However, the Blues claimed that in 16 of those cases, the players were registered in line with advice that the game’s global governing body had given the Football Association in 2009.
Chelsea argued that the alleged rules breaches in the remaining 11 cases were either “procedural” or there was no case to answer because of precedents set in Cas’ ruling on Spanish side Real Madrid’s transfer ban in 2016.
“Chelsea respects the importance of the work undertaken by Fifa in relation to the protection of minors and has fully cooperated with Fifa throughout its investigation,” added Chelsea.
“However, if Fifa continues to impose inconsistent and unequal sanctions on clubs then it will not only undermine the very purpose of the regulations, but it will also bring into doubt the game’s confidence in Fifa being able to appropriately regulate this important area.”