Barcelona triggered a €120m buyout clause to sign the Frenchman in July, but Atletico argued that the deal with the player was agreed before the clause dropped from €200m, making the Catalans obliged to cough up the larger amount.
Leaked emails later appeared to show that Griezmann had indeed negotiated his contract with Barcelona as early as March, to the point of being able to decide how much commission various members of his entourage were going to receive.
But a €15m payment from Barça to Atletico this week is nothing to do with Griezmann.
The €15m is believed to be a gesture that will give Barcelona first refusal on several Atletico players should they ever be sold. Centre-back Jose Gimenez and midfielder Saul Niguez are the first-team stars included in it, while there are also a handful of un-named academy players.
It essentially means that Atletico must give Barcelona an opportunity to match any future offer they wish to accept for the players covered by the agreement.
Mundo Deportivo specifically explains that this arrangement is effectively laying the groundwork for repairing a previously healthy relationship between the clubs that was damaged by the Griezmann saga.
Both David Villa and Arda Turan have also transferred from one to the other in recent years.