Barcelona municipal police estimated that about 80,000 people took part in the march organised by Societat Civil Catalana (Catalan Civil Society), the Xinhua news agency reported.
High ranking members of the Spanish Socialist Party (PSOE) of acting Prime Minister Pedro Sanchez, such as the Party Secretary Jose Luis Abalos and Foreign Minister Josep Borrell Fontelles, were also present, along with the leader of the PSOE's Catalan branch, Miquel Iceta.
Earlier in the day in a radio interview with Spanish National Radio (RNE) Iceta said that the events of the past fortnight was something the region would have to live with "for years."
Waving Catalan and Spanish flags under the march's slogan of "For coexistence, democracy and Catalonia. Enough," demonstrators called for an end to the violence of the past fortnight.
Sunday's demonstration followed a march that was attended by around 3,50,000 separatists, who protested against the sentences of between nine and 13 years given to nine separatist leaders on October 14.
Some demonstrators threw bottles, paint and eggs at police, who responded with baton charges, in scenes reminiscent of those seen just over a week ago in the same street.
The number of separatist demonstrators arrested over the past fortnight in the Catalan region has risen to 206 as reported by police sources.
( With inputs from IANS )