The Guggenheim Bilbao is forcing the removal of a provocative Paul McCarthy and Mike Bouchet 2,000 square foot mural installation on the side of a building in Bilbao, artnet News has learned. The billboard, on the side of a structure at 31 Gran Via, is an extension of an exhibition the two artists are having at the Portikus in Frankfurt. Their collaboration at Portikus includes mostly drawings, as well as a few sculptures, that depict museums as “self-serving mechanisms for their board members,” according to a press release. To make their point, the artists have defaced images of several famous museum facades—the New York Guggenheim Museum as a toilet bowl, for instance, or the Whitney Museum as a shoe-shine box.

McCarthy and Bouchet worked with an advertising agency in Bilbao to print a massive mural-like banner, that wraps the facade of a building, showing the Guggenheim Bilbao as an upside-down battleship. The idea was to protest that museums are often, from their point of view, “inconsiderate” of and don’t care about artists or the exhibition of artworks in preference for architectural statements.

Earlier today Alba Urresola, associate director of legal and internal control at the Guggenheim Bilbao, emailed Marlborough Chelsea, in New York, who represents Bouchet (McCarthy is represented by Hauser & Wirth) claiming that the image of the Guggenheim Bilbao is a registered trademark under Spanish Law and that the artists are breaking the law by using “without authorization” an image of the Frank Gehry-designed museum.

This is the second time in just a matter of weeks the institution has run afoul of the art world’s traditionally tolerant and liberal bent. Earlier this year, bugle-blowing protesters at the Fifth Avenue flagship sought to highlight the labor conditions on Saadiyat Island in Abu Dhabi, where the long-delayed satellite of the Guggenheim is set to be built.

In Bilbao, the museum claims that under Spanish law only it has the right to use images of the museum and therefore the artwork is an infringement of its copyright. The museum also objects to the connotations of the artwork, saying that it brings discredit to the institution. The museum asked that the banner be removed as soon as possible.

The artists have refused to do so, claiming that the image is in fact their artwork and that they are entitled to use images of the Guggenheim Museum Bilbao as the basis of a new creation under copyright laws, and, moreover, given that the artwork is not on museum property, they are not under any obligation to comply with the musuem’s request.

Following the refusal of the artists to remove the mural, the owners of the building received a fax from the museum late today demanding removal of the installation and again asserting that the use of the Guggenheim Museum Bilbao image was an infringement of its copyright. The building has granted the museum’s request, artnet News has learned, and the artists have since been informed by a building representative that the mural must be removed.

The exhibition at the Portikus runs through April 15 and then travels to Marlborough Monaco in July.