Neymar is set to become the most valuable footballer on the planet when a €222 million switch to Parc des Princes is finalised.
Goal understands that the Brazilian will say goodbye to his team-mates on Wednesday and could sign terms with PSG by the end of the week.
According to Tebas, however, the deal would be illegal and La Liga would not allow it to go through.
The head of the Spanish top flight insists that the court wrangling that continues to dog Neymar's move from Santos to Camp Nou makes a move impossible, as do UEFA's Financial Fair Play obligations.
"Even if PSG do not meet [Neymar's] release clause we are going to report them," Tebas told Sport on Tuesday.
"We have already warned the president of Paris Saint-Germain that we would do so and we see that PSG's policy has continued in the same manner.
"They cannot invent some numbers where their commercial rights exceed those of Real Madrid and Barcelona. Nobody believes that."
Sport has previously reported that Neymar's transfer could be blocked until the dispute over his previous deal is resolved.
Part of the fee paid by Barcelona for his signature back in 2013 remains in arbitration as several parties fight over the money received in bringing him to Spain.