A man has been sentenced to five years' jail for his part in one of Australia's most notorious art heists.In 2004, a remote property near Murwillumbah, on the New South Wales northern coast, was robbed.Owner John Opit alleged paintings worth $150 million were taken. Among them was an original work by French impressionist Paul Cezanne, Son In A High Chair. The authenticity of the painting has been disputed, but Judge James Black today told the Lismore District Court that was not a factor in the case. Brett Michael Williams, 47, had twice before failed to appear for sentencing. He turned himself in to Lismore police on Wednesday - his birthday. Today Williams was handed a five-year sentence, with a non-parole period of three years and nine months. The supposed Cezanne, meanwhile, has been recovered.It has been sent to a Queensland university for testing.