The regional government is planning on holding an independence referendum
Thousands of people have gathered in Barcelona to rally against Catalan independence.
They're rallying against a push by the regional government of Catalonia to break away from the rest of Spain.
Demonstrators marched under banners with slogans such as "No to Independence" and "Stop the Coup", a reference to the regional government's plan to hold an independence referendum by September.
The central government in Madrid has previously called the referendum unconstitutional.
Gloria Chicote, a 60-year-old nurse who moved to Barcelona 30 years ago said "I don't want independence, I am Spanish."
It was the first protest staged by the Catalan Civil Society, a platform set up in 2014 to oppose independence for Catalonia, a wealthy region in northeastern Spain that is home to 7.5 million people.
Barcelona city hall estimates 6,500 people took part in the march while organisers say around 15,000 showed up. The march finished outside the offices of the regional Catalan government.
Parties that want Catalonia, which has its own distinct language and customs, to break away from Spain won a majority of seats in the regional parliament for the first time in local elections in 2015.
Demands for autonomy have been fuelled by Spain's economic downturn, leading many to resent sending tax money to Madrid.
The head of the Catalan Civil Society, Mariano Goma Otero said "The battle is not completely lost. It is reversible but Madrid needs to be much more present in Catalonia."
"The central government in Madrid should boost investment in infrastructure projects in Catalonia and be more sensitive to the region's language and culture."