FIFA have banned Spanish clubs Real Madrid and Atletico Madrid from registering players for the next two transfer windows.
The La Liga giants have been punished by the world governing body for breaching rules over the transfer of players aged under 18.
The ban does not cover the current transfer window, which runs until the end of this month.
Atletico were fined 900,000 Swiss francs, while Real were told to pay 360,000 Swiss francs.
The clubs have the right to appeal against the decision.
Barcelona were given the same penalty in April 2014 for also breaching rules on the transfer of under-18 players.
Their ban, which ended this month, did not stop the La Liga side from signing players.
They bought Arda Turan and Aleix Vidal in the summer of 2015, though both players were prevented from playing until the current window opened.
The next two transfer windows are July/August 2016 and January 2017.
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