The Spanish Football Federation (RFEF) on Thursday fine FC Barcelona, 300 euros only for their approach to Antoine Griezmann, while he was at La Liga, rivals Atletico Madrid.
Spanish champions Barcelona signed Griezmann after paying his 120m-euro (£107m) buyout clause on 1 July.
But the federation said Barca broke its rules by negotiating with Griezmann without Atletico’s permission.
Atletico believed his buyout clause should have been 200m euros (£179m).
They claimed that Barca began talking to the player in March, when that was the size of his buyout clause.
His cost then dropped to 120m euros at the start of July, which was when he signed for Barca, but Atletico claimed the “commitment of the player and Barcelona was closed” prior to the clause reducing.
The player was absolved of any responsibility by the federation.
The RFEF’s statement read: “Taking into account the economic capacity of the club and the amount of the fine, this committee is aware that the payment of 300 euros, beyond its merely symbolic character, will not damage the sanctioned club and, probably, will not persuade other clubs in the same situation in the future to adjust their conduct to the regulations.”
However, the RFEF determined that was “not a sufficient reason” to impose a one-match closure of the Nou Camp – its only other possible sanction – which it says is reserved for “infractions of a different nature”.
Griezmann – who had announced in May he would leave the Madrid side – signed a five-year deal with Barca, which includes an 800m euro (£717m) release clause, to become the world’s sixth most expensive signing.
Following the move, Atletico released a statement in which they expressed their “strongest repulsion for the behaviour of both, especially Barcelona”.
The Madrid club previously reported Barcelona to Fifa over an alleged illegal approach for Griezmann in December 2017.
With BBC Sports report