Workers removed a large banner from a balcony on the front of the centuries-old palace, which said in Catalan and English "Free political prisoners and exiles." That referred to the prosecution and self-imposed exile of Catalan separatist leaders for their role in a failed attempt to declare independence in 2017.
Elected officials and public institutions are prohibited from expressing support for one particular party or ideological position during a campaign period. Spain's general election is on April 28. On Thursday, the regional government removed a different banner which displayed a yellow ribbon symbol used to express support for the prisoners.
The electoral board deemed the ribbons to be an unacceptable "tool of political propaganda" and ordered their removal earlier this month. But Quim Torra, Catalonia's regional president who always wears a small yellow ribbon in his lapel, asked for more time to do so and argued that it was an issue of free speech.
Meanwhile, opposition parties chided the socialist government for not taking a harder line with the secessionists. The public prosecutor's office announced Friday it is opening an investigation into Torra's conduct for possible disobedience.
Torra has said he will challenge the electoral board's order in court.