La Liga president Javier Tebas has threatened legal action if UEFA fail to properly investigate what he feels are clear breaches of the organisation's Financial Fair Play rules by Paris Saint-Germain.
The grounds of Tebas' complaint are not made clear in an interview with Mundo Deportivo, but he said PSG's desire to pay Neymar's €222 million buyout clause is not his only issue.
"We will [make a complaint about PSG] because they infringe UEFA's Financial Fair Play rules and also the European Union's competition rules," Tebas said.
"We will make a complaint to UEFA and if they don't do anything we will take it to the competition tribunals in Switzerland and Brussels. And, from there, we don't rule out going through the courts in France and Spain.
"It's not [just to do with Neymar]. We planned [to make the complaint] earlier. If we've not done it sooner it's because we planned to take the problem to UEFA's people first and I said that to president [Aleksander] Ceferin, but there hasn't been time.
"What worries me is La Liga can't just sit around with its arms crossed. It's not about Barca, it's about Spanish football. Today it is Barca but tomorrow it could be Real [Madrid], Atletico or another team."
Asked if he'd already made the complaint, Tebas added: "We're going to make it immediately."
The La Liga chief also confirmed that he's already informed PSG president Nasser Al-Khelaïfi of his intentions.
"Two months ago I received the president of PSG at La Liga's offices and I told him what we were going to do and the reasons why," he added.
"He was angry with me and said that he did not understand. We have a relationship because don't forget that [BeIn] manage the television rights for Spanish football, but La Liga must defend our clubs in these situations."
UEFA have previously punished PSG for falling foul of FFP legislation.
The Ligue 1 club were ordered to play past editions of the Champions League with only 21 players in their squad and spending on new signings was capped at around €55 million one year as punishment for breaching the rules.
They were also fined €20m a year for three years totalling €60m, but only the first year's fine was imposed.
However, UEFA's FFP head has said that PSG will have "done their sums well" to ensure a potential world-record move for Neymar keeps them within financial fair play regulations.
In addition to paying the Brazilian's buyout clause, PSG also have to work out how to fit the forward's reported €30m post-tax annual salary into FFP regulations.