Spaniards are locked in a furious debate about privacy and the press. They are asking to what extent people should be entitled to protection from prying photographers if they are not a celebrity in their own right but are related to one.

Last week a court in Toledo became the latest battleground as Telma Ortiz, the 35-year-old sister-in-law of Prince Felipe, the heir to the throne, sought a restraining order against 50 media organisations – from gossip magazines to television stations – that she claimed had turned her life upside down.

Ortiz and her boyfriend, Enrique Martin Llop, are aid workers who claim to be under constant harassment from photographers, particularly since Ortiz gave birth to her daughter Amanda in March.

Fernando Garrido Polonio, her lawyer, says that being “paparazzi fodder” is intolerable for what he calls “ordinary citizens” who are not famous and do not want to be famous. They are obliged to go to extraordinary lengths to protect their privacy and keep their faces out of the magazines, he says.

“They have to think twice about every movement they make, sometimes turning down meetings with friends and family members,” Polonio remarked, referring to dangerous car chases reminiscent of the one in which Diana, Princess of Wales, died in a tunnel in Paris.

“They are pushed and shoved so as to provoke an angry reaction; their path is blocked to their home, their car, the shops, until the desired image is obtained,” he said.

“There are fights between the image hunters that could rebound on anyone close to them. They have even been pursued in countries other than Spain.”

However, the judge confirmed an earlier ruling in May that any restraining order would be “legally unviable” because, whether she likes it or not, Ortiz – as the sister of Felipe’s wife, Princess Letizia – is in the limelight.

The case shed light on the trials endured by the Ortiz family since Letizia’s marriage to Felipe in 2004. In a tragedy apparently unrelated to the burden of life among royals, Erika – another sister of Letizia – committed suicide last year.

The princess herself has struggled to come to terms with being the subject of so much scrutiny, including complaints about her “anorexic” appearance and speculation about a nose operation earlier this year.

A former journalist, she has given birth to two daughters, but even that does not seem to satisfy the wagging tongues in royal circles: pressure has been mounting on her to produce a male heir.

In the case of her sister, lawyers defending the media have argued that since Telma enjoys some of the privileges of being related to the royal family – she is often invited to public functions and is said to have stayed at Spanish embassies while abroad – she should not complain about the drawbacks.

Adding insult to injury, as well as losing her court case Ortiz was ordered to pay costs of €45,000 (£36,560). Not surprisingly, perhaps, she is considering moving back to the Philippines, where she worked for a Spanish overseas aid agency until returning home to give birth earlier this year.

The case has focused attention on a privacy law that critics say does not draw a clear enough line between who is and who is not fair game for the media. Politicians are thought to be included in the first category, but, unlike Britain or America, Spain pays scant attention to the private lives of its leaders.

This could be because they are dull: the most interesting item of gossip that surfaced about Jose Luis Rodriguez Zapatero, the prime minister, during his reelection campaign earlier this year was that he enjoyed fishing and walks in the mountains.

The royals, by contrast, have always aroused interest, and Felipe, at least, has had more luck in the courts than his sister-in-law.

Two cartoonists were fined €3,000 (£2,400) each last year for insulting the heir to the throne in a drawing that showed him making love to Letizia and saying to her (in a reference to the government’s new cash bonus to mothers): “Do you realise that if you get pregnant, this will be the closest to real work I’ve ever done?”

Football players have also been successful in cases against the media: a Barcelona court ordered compensation of €600,000 (£490,000) to five players who were reported to have engaged in an orgy in a Madrid hotel on the eve of a big game in 2002.

Ortiz’s mistake may have been to target too wide a spectrum of “people” magazines: Lawyers in court argued that to block them from photographing Ortiz would be the equivalent of censorship.

At the same time, some have argued that it was not for a court to decide whether or not Ortiz was a newsworthy subject.

“Some might consider that there is no interest attached to the question of whether Telma Ortiz wears red or beige,” wrote a commentator in El Pais newspaper. “But the public does not think so.

“The modern range of tastes and choices, desires and standards, has little to do with the pontifications of the legislator.”

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