Batman is a comic book character created in 1939 by Bill Finger and Bob Kane. Valencia CF is a soccer team (or “club” if you want to be fancy) that was founded in 1919. Batman wears a bat on his chest to strike fear into the hearts of criminals, a superstitious and cowardly lot. Valencia has a bat on their team crest, presumably to strike fear in the hearts of other football clubs, who may or may not be superstitious and cowardly. As you can see, there is a lot of room for confusion there—Batman fans have a long history of wandering into soccer games unawares, mistaking them for comics conventions.
According to BBC Sport, DC Entertainment, owner of the Batman trademark, has filed an opposition letter with the Office of Harmonization in the Internal Market—the branch of the European Union that handles trademarks, claiming that Valencia’s Bat-symbol is too similar to Bruce Wayne’s bat-symbol. As most people will note, the 20-year head start Valencia has on Batman will probably work in their favor.
DC did not respond to EW‘s request for comment.