When the Spanish tycoon Julio Muñoz Ramonet died in Switzerland back in 1991, he left his remarkable art collection to the local authorities in Barcelona. Twenty three years later, the Spanish and Catalan tax offices are asking Muñoz Ramonet’s daughter, Alejandra Muñoz Villalonga, to pay €4 million in inheritance taxes, El País reports.

Tax authorities claim that shortly before and after the death of the industrialist—whose fortune flourished during Franco’s dictatorship—a number of actions were taken by his daughters to create a “legal screen” around his assets. Those actions include creating new company shares distributed among Muñoz Ramonet’s four daughters as well taking out new insurance policies to transport some 300 artworks from Barcelona to Madrid. The Catalan court has found that the moves constitute an “indirect business” that is subject to inheritance taxes.

But Muñoz Villalonga is putting up a fight, refusing to pay the amount, which was initially requested in 2006. She has appealed the ruling. She is also continuing a long-standing legal dispute concerning the ownership of the art collection, which Muñoz Ramonet donated to the city of Barcelona, along with the palace that housed them (see “Industrialist’s Daughters Sue Barcelona To Keep Goya, El Greco, and Other Masterpieces“).

Despite what was stipulated in Muñoz Ramonet’s will, local authorities only managed to obtain the approximately 2,000-work-strong collection last year. And, even then, not all the works were found. According to El País, when specialists entered the Muñoz Ramonet’s former home in the center of Barcelona in summer 2013, they discovered that the best works from the collection—including paintings by Francisco de Goya, El Greco, Rembrandt, Claude Monet, Diego Velázquez, Raphael, and Titian—where nowhere to be seen. The masterpieces are thought to be in Madrid, having been relocated following on the orders of Muñoz Ramonet’s daughters (see “Barcelona Sues Disinherited Daughters for Stealing Artwork Bequeathed to the City“).