The anti-capitalist party's action focused on placing posters at various bus shelters in the city with three clear messages: “There is no peace within NATO,” “There is no peace without self-determination,” and “Peoples of the world, let us rise up.” This initiative aims to highlight their opposition to military alliances and defend the right of peoples to decide their future.

In parallel, the CUP has sent a letter to several international leaders present at the Barcelona summit. In this document, the party outlines what it considers to be contradictions presented by the Spanish state. They argue that Spain cannot position itself as a defender of peace while being part of NATO, increasing military spending, and simultaneously denying the right to self-determination of peoples.

Among the recipients of these letters are prominent figures such as Claudia Sheinbaum from Mexico, Yamandú Orsi from Uruguay, Lula da Silva from Brazil, Cyril Ramaphosa from South Africa, and Gustavo Petro from Colombia.