Real Madrid and Atletico Madrid have been banned for two consecutive transfer windows by FIFA for illegal transfer dealings.
The pair will not be allowed to register new players for the summer transfer period and the next winter window, meaning neither side will be able to make additions to their squad until the summer of 2017.
Atletico were fined 900,000 Swiss francs (£622,000), while Real were told to pay 360,000 (£249,000). A statement from FIFA this morning read: "The two clubs were found to have violated several provisions concerning the international transfer and first registration of minor players as well as other relevant provisions with regard to the registration and participation of certain players in competitions."
According to reports in Spain today, the punishment handed out to Real Madrid, which is the same doled out to Barcelona last year, was in part down the transfer of manager and club legend Zinedine Zidane's son, Luca.
The 17-year-old goalkeeper is part of Madrid's youth set-up - and Sport newspaper report, using Radio Onda Cero Radio as a source, his switch to the Spanish capital was one of the cases that led to his father's team being punished.
Sport's English Twitter account carried a translation of a tweet from the radio show, which read: "Zidane's own son, Luca, was one of the cases which Real Madrid are being punished for (per Onda Cero radio)"
There are strict rules in Europe over the movement of players, which limit how far young players can travel to play.
Both Madrid clubs have the right to appeal, and are yet to make an official comment over the punishment. The ban could have huge implications for other clubs across Europe, including Manchester United who have been linked with a move for Cristiano Ronaldo, and almost lost David de Gea to Real over the summer.
During their ban, Barcelona were able to sign players, such as Arda Turan from Atletico Madrid, but were blocked from registering players, meaning the Turkish international only made his debut last week.