The judge at a federal court in Rio de Janeiro on Friday found Barcelona forward, Neymar, guilty of tax fraud for failure to report earnings from his contracts with Santos, Barcelona and Nike.
The court has therefore ordered him to pay 188.8 million Brazilian reals (€45.9m) in fines and back-taxes.
La Folha de Sao Paulo reports that Neymar was found guilty of tax evasion by an administrative court of the Federal Revenue in Rio de Janeiro.
The Brazil international will have the opportunity to appeal the decision.
According to the court, the decision was taken after Neymar failed to pay at least $63.6m reales through his management companies between 2012 and 2014. The Brazilian is also alleged to owe $125.2m reales in fines and interest.
Neymar is also facing allegations of corruption and fraud in Spain in relation to his transfer from Santos to Barcelona in 2013.