Mrs McCann was delivering a personal statement at Lisbon's Palace of Justice in the libel case brought by her and husband Gerry against Goncalo Amaral over claims he made in a book about their role in the disappearance of their daughter from the family's holiday apartment in Praia da Luz in the Algarve in 2007.
She told the court her son Sean heard about Amaral's allegations on the radio while travelling on the school bus.
"Sean asked me in October 'Mr Amaral said you hid Madeleine'. I just said that he said a lot of silly things," she said.
Sean and his twin sister Amelie were aged two when Madeleine, who was nearly four, went missing.