La Liga has filed a complaint to UEFA against Paris St Germain and Manchester City over alleged Financial Fair Play violations, the Spanish professional football league announced.
The organisation said it would take "further legal action against the European Union, France and Switzerland" justice systems as it understands that "these clubs are continually breaching the current regulations" of financial fair play.
La Liga said it complained to Manchester City to UEFA in April before filing the one against PSG last week.
La Liga president Javier Tebas said last month the organisation would take legal action against the French club after Kylian Mbappe snubbed a widely-tipped move to Real Madrid at the 11th hour and renewed his contract with PSG until 2025.
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La Liga reacted angrily to Mbappe's contract extension, saying PSG's new offer to Mbappe "attacks the economic stability" of European football.
"It is scandalous that a club like PSG, which last season reported losses of more than 220 million euros ($232.32 million) after accumulating losses of more than 700 million euros in prior seasons ... with a squad cost around 650 million for this season, can close such an agreement," La Liga said at the time.