The 42-year-old, a sister of Crown Prince Mohammed bin Salman (MBS), the de facto ruler of the oil-rich Gulf state, had been charged with instructing her bodyguard to beat, hold captive and humiliate the plumber.
Bint Salman, a daughter of King Salman, was tried in absentia following an arrest warrant issued in December 2017. She did not show up for the trial since it kicked off in July this year.
She was also ordered by the Paris court to pay a fine of 10,000 euros ($11,000).
The punishment was heavier than that demanded by the prosecutors, who had sought a six-month suspended sentence and a fine of 5,000 euros ($5,480).
The princess was accused of instructing her bodyguard Rani Saidi to beat up Ashraf Eid after he was seen taking pictures inside her home in September 2016.
She had been charged with complicity in an act of intentional violence, complicity in illegal confinement and complicity in theft.
The bodyguard, who was the only protagonist in the case present in court, was handed an eight-month suspended sentence and a 5,000-euro fine, in line with the recommendations of prosecutors.
The lawyers for the princess and Saidi said they planned to appeal, saying the case was based on unfounded allegations while also questioning the conduct of Eid, who presented a 21,000 euros ($23,000) bill for the work just days after the events.
Emmanuel Moyne, a lawyer for the princess, contended that Eid’s statements had “largely been fanciful” and said he had in no way been forced to stay in the apartment.
“We will prove the innocence of Princess Hassa bint Salman at the court of appeal in Paris,” he said.
Saidi’s lawyer, Yassine Bouzrou, said the ruling was “incomprehensible” and accused the court of ignoring key elements that would have proven the innocence of his client.
Eid was working on the seventh floor of the luxury apartment block owned by the Saudi royals on Avenue Foch, a favourite destination of foreign millionaires in Paris, when he was called to the fifth floor to repair a damaged washbasin.
He took pictures of the toilet which he told investigators he needed to carry out his work. Eid claims that the princess flew into a rage after he caught her reflection in a mirror on camera.
He said he was also tied up and ordered to kiss the feet of the princess, who is lionised in Saudi state-run media for her charity work and women’s rights campaigning.
The plumber said he was allowed to leave the apartment only after several hours, during which his phone was destroyed, and that at one point the princess shouted: “Kill him, the dog, he doesn’t deserve to live.”
Georges Karouni, Eid’s lawyer, praised the “strength” of his client during the investigation.
“My client was right to trust the law,” he said, adding that the court had been “extremely sensitive” to the seriousness of the facts.
Saidi argued during the court hearings he had merely come to the aid of the princess in a tussle with Eid where he feared the plumber was taking photos to sell to Arab media outlets.
A civil hearing is scheduled for March 5 over possible damages.
The case is the latest blow to the image of the kingdom.
Social and economic reforms have been badly undermined by the imprisoning of female activists and by the murder of dissident writer Jamal Khashoggi at the Saudi consulate in Istanbul last year.
MBS is also seen as the driving force behind the Saudi military intervention in Yemen, where tens of thousands have died.
Agnes Callamard, a United Nations special rapporteur on extrajudicial executions, reported “credible evidence” last month that linked MBS to the killing of Khashoggi, who was strangled and dismembered inside the consulate.