The footballer, who led Italy to World Cup glory in 2006, broke a police seal at his home in Naples after it was seized by authorities last October as part of an ongoing investigation into alleged tax evasion.
His wife, Daniela Arenoso, and brother, Paolo, were also convicted of breaching the ban on entering the property, Il Mattino reported. Both were given sentences of four and six months, respectively.
The three also faced accusations of failing to secure planning permission for works carried out on the house and surrounding area, but were acquitted.
Cannavaro is being investigated on suspicion of running a sham company to avoid paying more than €1 million in tax.
He had property and other assets worth €900,000 confiscated in connection with the probe into a luxury boat rental business that the 41-year-old ran with his wife.