Barcelona may be forced to close the Nou Camp as part of their punishment if found guilty of a premature agreement with Antoine Griezmann.
Atletico Madrid allege that the Catalan side completed the signing of their former striker before his release clause fell from £177million to £106m on July 1.
Barcelona paid the release clause at La Liga headquarters in July but Atletico sought court action that could lead to a stadium ban for their domestic rivals, according to El Mundo.
Barcelona have previously been forced to host a La Liga match in an empty stadium.
Their 3-0 win against Las Palmas in October 2017 was closed off to supporters due to violent clashes in the city during the Independence referendum vote.
Juantxo Landaberea is the investigating judge in the case and thinks closure of the Nou Camp would be adequate punishment if the Spanish champions are found guilty.
Any precedent for a stadium ban as punishment is outlined in articles 88 and 126 of the disciplinary code.
The case must come to fruition and there is now no option for Atletico to drop their claim under national law.
One alternative is a pitiful fine of just £266 according to regulations but as this is such a low amount, Landaberea is weighing up more severe alternatives – one of which would see Barcelona play a game behind closed doors.
While the two clubs continue their public legal row over the transfer of the Frenchman, Griezmann has shown no signs on the pitch that it has distracted him.
He scored twice in the 5-2 win over Real Betis — and added an assist — before finding himself involved one more in the weekend rout over Valencia.
Heading to Germany to take on Borussia Dortmund in the Champions League on Tuesday, Griezmann could line up alongside Luis Suarez and Lionel Messi for the first time after the Argentine was named in the 22-man travelling squad.
Messi has been forced to watch from the sidelines so far due to an ongoing calf injury and Griezmann has been tasked with leading the attack in his absence.