During the October 1st independence referendum, which was banned by Madrid, prosecutors say the Mossos d'Esquadra regional police force demonstrated “total passivity” under Trapero's watch, while Spain's national police led a crackdown using batons and firing rubber bullets in a bid to stop voters.
Another Mossos director and a senior official of Catalonia's regional interior ministry have also had their charges downgraded while a fourth had already been charged initially with sedition.
The officials face a 10-year jail term if they are found guilty of sedition although the prosecutor also indicated that, if not proven, the charge might be reduced further still to disobedience.
The alteration of the charges follows the decision of the Supreme Court in October to dismiss the charge of rebellion against the nine separatist leaders, finding them guilty of sedition.
The trial, which began in January, had been suspended due to the coronavirus pandemic.