Amid heightened fears over terrorism, people who saw the 13-year-old from the windows of surrounding buildings thought the gun was real, and so didn't waste any time in calling the police, Corriere reported
In turn, the police wasted no time in getting to the garden, immediately surrounding the potential assailant.
But when they told him to drop his weapon and lie down, he refused.
A few minutes later, they realised the gun was a toy and that the boy was wearing his hood to shelter from the rain.
But this isn't the first time a toy gun has sparked panic in Italy since the Paris terror attacks. Just days after the November 13th carnage an American man living in Rome said he was briefly detained after police mistook a toy gun and Halloween costume in his parked car for a security threat against Pope Francis.
The car was parked on Corso Vittorio Emanuelle II, along which the papal convoy had been due to pass on return from a visit to a nearby church.
A few weeks later an Italian journalist was charged with “creating false alarm” after entering St Peter's square with a fake gun to film a feature about security during the Catholic Jubilee of Mercy.