"This means so much to me. Now I can move on with my life. I believe in the law again," Eliza Söderman told the TT news agency.
In the judgement revealed on Tuesday the Grand Chamber declared that there had been a violation of article 8 (right to respect for private life). The court added that Sweden had to pay the girl €10,000 (89,000 kronor) in damages plus €29,700 to cover costs and expenses.
Eliza Söderman, who is now 25, took the case to the European Court of Human Rights in Strasbourg after her stepfather was acquitted by the Swedish court of appeal in 2007.
He had previously been charged with sexual molestation but argued that he never intended for his stepdaughter to know about the secret filming.
"The Court found that Swedish law in force at the time had not ensured protection of Ms Söderman’s right to respect for private life – whether by providing a criminal or a civil remedy – in a manner that complied with the Convention.
"The act committed by her stepfather had violated her integrity and had been aggravated by the fact that she was a minor, that the incident took place in her home, and that the offender was a person whom she was entitled and expected to trust," said the European Court of Human Rights in a press statement.
According to court documents the original incident took place in September 2002 when the girl was 14-years-old. She discovered a video camera hidden in the laundry basket of the bathroom and brought it to the attention of her mother.
"The stepfather took the camera from the mother. Subsequently, the applicant saw her mother and stepfather burn a film, but she was not sure whether it was a recording of her," according to the summary of the case published on the European Court of Human Rights website.
In Tuesday's ruling of the case, which was called Söderman V Sweden, the court said that the plaintiff had not complained about the effectiveness of the criminal investigation carried out by the Swedish authorities.
"The question before the Court was whether, in the circumstances of the case, Sweden had had an adequate legal framework to protect Ms Söderman against the actions of her stepfather, in compliance with its obligations under Article 8," said the court in a press statement.
Söderman said she now just wants to get on with her life and added that the money, which is the equivalent of 350,000 kronor, was a "huge bonus."
"I was not prepared for it, I just wanted wanted things to be done right. It's an incredibly huge bonus," she told TT.
Söderman added that she had "wonderful support" from her family, friends and legal team over the years.