Despite the Mediterranean vocation in the choice of some guest cities over the years (such as Beirut, Istanbul and Lisbon), Rome is the first Italian city to take part in the festivities for La Mercè. Barcelona and Rome share common areas of work, for instance in drafting the Charter of Rome on human rights. Barcelona also has a solid Italian community and institutions such as the Escola Italiana and the Institut Italià de Cultura de Barcelona.

The artistic strength of the Italian capital, home to an infinite number of high-quality projects in theatre, music and film, will be represented at the festivities and form part of the programmes for the Mercè Arts de Carrer and the Mercè Música.

After two years of the pandemic, this is also a way of recovering normality for these celebrations through the invitation of a city. This formula helps form unique bonds of cooperation and at the same time enriches the cultural programme. Havana took part in 2021, but in 2020 the health crisis meant there could be no guest city. In the year before the pandemic, Beirut was the guest city.

The first year Barcelona invited a guest city to take part in La Mercè was in 2007, with Medellín the chosen city on that occasion. After that, in chronological order, came Quito (2008) Istanbul (2009), Dakar (2010), Sant Petersburg (2011), Montreal (2012), Vienna (2013), Stockholm (2014), Buenos Aires (2015), Paris (2016), Reykjavík (2017), Lisbon (2018), Beirut (2019), Barcelona (2020) and Havana (2021).