In finding Giovanni Colasante, 46, a local politician from Canosa di Puglia in southern Italy, guilty of assault, the court fined him 6,600 kronor ($990).
They were in the Swedish capital on vacation as part of a cruise that was to take them to several Nordic countries.
But when Colasante's 12-year-old son refused to go into the restaurant, the boy's father reacted and, according to witnesses, attacked the young lad.
“He lifted his son up by the hair,” eye witness Deniz Cinkitas told the Aftonbladet newspaper following the incident.
Other guests at the restaurant called police and Colasante was placed under arrest for breaking Sweden's laws outlawing corporal punishment, putting a dent in the remainder of the family's travel plans.
While no one denies that a disagreement took place, exactly how Colasante may have treated his son remains a matter of interpretation.
According to the district court's ruling, four witnesses testified to seeing Colasante pull his son's hair before rushing over to prevent any further violence.
However, testimony regarding the blows that Colasante allegedly dealt out was less certain. As a result, the Italian politician was convicted of abuse based solely on having pulled his son's hair.
Despite the fact that an adult was seen to have committed violence against a child, the court deemed the assault to be minor as Colasante only caused his son pain for a few seconds.
In deciding on Colasante's punishment, the court took into account that he has been held by police since his arrest.
The fact that Colasante was held against his will and saddled with travel restrictions is unusual for minor offences, but occurred in this case because the court wanted to make sure that he didn't leave the country.
The Italian embassy in Stockholm refused to comment on the verdict, but confirmed embassy official had been in contact with Colasante.
“We have just gotten word of this sentence, and he will discuss with his lawyer what he will do next,” Caterina Gioiella, embassy First Secretary told The Local.
Colasante's case has garnered a great deal of attention in the media in Italy, which is among the 11 EU countries without a law forbidding corporal punishment.
Sweden was the first to introduce a formal ban on corporal punishment back in 1979 and a slew of countries have since followed suit. The Swedish ban has faced scrutiny and been roundly criticised in some areas of the Italian media.
Mali Nilsson, responsible for the international work on corporal punishment at Save the Children Sweden, has followed the debate in Italy.
She has concluded that the discussion has been based on an incorrect view of Swedish legislation.
"It is thought that the law is intended to criminalise parents and that neighbours should report one another. But we know that the law has not led to more parents losing their children. Nor was that the intention; the purpose is preventative - to protect children," she said.
Of the EU's 27 member states, 16 have a law against corporal punishment. In Italy it is expressly forbidden in schools, but not in the home.
Save the Children Italy lobbies for a change in the law, but has noted that Colasante's case has stirred such strong emotions in the country that a planned campaign on the issue could be put on ice, Mali Nilsson explained.
"They may have to wait with their campaign. But my colleagues also say that the case has at least prompted a debate, and that could be something," she said.