Spanish prime minister Mariano Rajoy urged businesses not to abandon Catalonia after hundreds of firms moved their legal headquarters away as uncertainty over the region's independence drive drags on.
A demonstration is being held in Barcelona later today by supporters of Catalan independence.
Forcadell was one of several dismissed Catalan officials to be detained after their shock decision last month to declare the region of 7.5 million people independent from Spain.
Catalonia's regional government went ahead with an October 1 referendum on independence despite Spanish authorities deeming it illegal.
The Spanish government responded to the referendum by dissolving the Catalan parliament, imposing direct rule, and calling a snap regional election on 21 December.
"Freedom for the political prisoners", protesters shouted as they marched along Avenue Marina from the beach to the Sagrada Familia church.
Despite opposition to the early election imposed by Madrid as a way to resolve the impasse, the two leading pro-independence parties, PDeCAT of deposed leader Carles Puigdemont, and the ERC, have said they will participate.
Some 54 per cent of Spaniards evaluate positively Madrid's handling of the Catalan crisis, but only 28 per cent of Catalans share this view, according to a poll for newspaper El Pais.
Ms Colau, who was elected in 2015 on an anti-capitalist platform and whose party is standing in the regional parliamentary election for the first time, said leaders of the independence movement had "tricked the population for their own interests". I just want to carry out what my parliament has approved.