Atletico Madrid have reported Barcelona to La Liga as they continue to pursue an €80 million (£72m/$90m) addition to the transfer which has taken Antoine Griezmann to Camp Nou.
A World Cup-winning forward has completed a move from the Spanish capital to Catalunya.
Barca have paid out the €120m (£108m/$135m) required to trigger the release clause that existed in his Atletico contract.
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They believe they have done nothing wrong, but domestic rivals are arguing that an agreement was reached with Griezmann when his exit fee stood at €200m (£179m/$224m).