The girl's parents had planned to leave as a family along with her brother, aged seven, on a makeshift boat from the coastal town of Sayada and head towards the Italian island of Lampedusa, as increasing numbers of other Tunisians have done.
But according to the Tunisian Forum for Economic and Social Rights (FTDES), which closely tracks clandestine migration from Tunisia, the father had "handed his daughter over to the smuggler on the boat" before retracing his steps from the embarkation point "to help his wife and son who were far behind".
"In the meantime, the boat left for Lampedusa," it said.
Her return comes after a judge in Sicily ruled she should be sent home on a request by Tunisian authorities.
The North African country's families ministry, in a statement, said a Tunisian child protection delegate accompanied the girl on the trip home, "and handed her to her family upon arrival at Tunis-Carthage airport."
Her parents, street vendors in coastal Tunisia, were detained over the incident but later released.
The FTDES says about 2,600 Tunisian minors, more than two-thirds of them unaccompanied, reached Italy between January and August, out of a total of around 13,000 Tunisian migrants.
A deep economic crisis is pushing growing numbers of Tunisians to attempt to reach Europe, particularly Lampedusa which is about 130 kilometres (80 miles) off the coast.
Authorities in the North African country of 12 million, under pressure from Europe to stem the flow, are struggling to intercept those who leave.