Protests erupted in Brazilian cities on Wednesday after President Dilma Rousseff named her predecessor Luiz Inacio Lula da Silva chief of staff and a taped telephone conversation fed opposition claims the appointment was meant to shield Lula from prosecution.
Police said 2,500 people demonstrated outside the presidential palace in the capital of Brasilia and others flocked to Sao Paulo's main Avenue Paulista.
Dozens of opposition lawmakers interrupted a session of Congress, chanting for Rousseff to resign.
Lula has immunity from all but the Supreme Court after his nomination as Rousseff's chief of staff was published in a special edition of the Official Gazette. State prosecutors had charged him with money laundering and fraud, and asked for his arrest.