The Spanish football division's complaints come just weeks after La Liga Champions Real Madrid failed in of Paris Saint-Germain star Kylian Mbappe.
The Los Blancos were also reported to have been interested in former Borussia Dortmund striker Erling Haaland.
Kylian Mbappe was strongly linked with a summer move to the Santiago Bernabeu on a free transfer.
Spanish publications had even already reported the proposed move as a lifelong dream of the the French superstar.
However, in a dramatic turn of events, the 23-year-old forward instead opted to extend his deal with the French Champions in a blockbuster contract renewal, that will see him become unarguably the highest earner in the sport.
Meanwhile, Norwegian sensation Erling Haaland, who had also been strongly linked with a move to Real Madrid, ended up joining his boyhood club Manchester City, completing a move to the Premier League champions in what he described as 'a perfect fit'.
In light of this, La Liga president Javier Tebas and the Spanish football division have launched complaints against both Paris St Germain and Manchester City, on the grounds of suspected breaches of Financial FairPlay regulations.
La Liga confirm they have filed Manchester City and Paris St Germain over FFP breach
The complaint was made known via an official statement, by Spanish newspaper Marca, that read:
"La Liga this week filed a complaint with UEFA against PSG, which will join another against Manchester City in April, for understanding that these clubs are continuously breaching the current financial fair play regulations."
"La Liga considers that these practices alter the ecosystem and the sustainability of football, harm all European clubs and leagues, and only serve to artificially inflate the market, with money not generated in football itself."
"La Liga understands that the irregular financing of these clubs is carried out, either through direct injections of money or through sponsorship and other contracts that do not correspond to market conditions or make economic sense."
"The complaints against Manchester City before UEFA were made in April and this last week the one corresponding to PSG has been presented, although it is not ruled out that in the coming days extensions of some of these complaints will be made with the contributions of new data."
"Additionally, La Liga has contracted law firms in France and Switzerland, including the French firm of lawyer Juan Branco, with the aim of undertaking administrative and judicial actions before the competent French bodies and before the European Union as soon as possible."
Javier Tebas hits out at Manchester City's Haaland deal
Javier Tebas was has also frowned at Manchester City's successful pursuit of Erling Haaland.
Tebas further raised concerns over the Premier League club's ability to complete such a high-profile move given the total amount of expenses that were at stake in the deal.
They must have done something, because (Erling) Haaland asked the clubs for more apart from the €60 million that has been paid." Tebas said.
This isn't the first time Tebas has led such complaints to the European Federation and it certainly won't be last.