It is understood that the Duke and Duchess of Cambridge are to instruct lawyers to commence proceedings in France against a photographer who secretly took pictures of Kate Middleton topless by a swimming pool, reports The Daily Telegraph.
The photographs, which initially appeared in a French gossip magazine, have now been published widely on the internet and in several publications including The Daily Star in Ireland.
The legal action is also likely to name the French magazine that first published the photographs.
Lawyers representing the couple will make a formal complaint in Paris under French criminal law for breach of privacy. The action is likely to include a request for an injunction against further publication of the images. French law imposes a maximum £36,000 fine and a prison sentence of up to one year for those found guilty of the offence.
A spokesman for St James' Palace confirmed yesterday that the couple would be making a complaint to the French authorities.
"The complaint concerns the taking of photographs of the Duke and Duchess of Cambridge whilst on holiday and the publication of those photographs in breach of their privacy," a statement read.
It is understood that the couple will not seek further injunctions in other countries where publication has or may be about to occur. Instead they have appealed to the media to act with decency.
The law in France
The French have a strict privacy law which makes it an offence to publish any information about an individual's private life without their permission. French judges have also shown a willingness to be creative when determining punishment: in 2009 a French magazine was ordered to blank out half of its cover and to display the wording of a privacy judgment against it.
However, the penalties for breaching privacy law in France are so small that publications can and will invade privacy when they believe that doing so will shift more magazines. In these cases the cost of the punishment seems not to fit the benefit of the crime.
However, the French press acknowledges that the privacy laws do keep it in check. Laurence Pieau is editor of Closer.
"It is very hard here in France... the privacy law is very restrictive but our readers are interested in what people are doing, how they dress, how they do their make-up," he said in a recent interview with the BBC.
The law in the UK
The picture in the UK is far less clear cut, with the only specific right to privacy enshrined in the Human Rights Act 1998. However, the UK law also provides for a defense in circumstances which the breach of privacy is justified on national security, public safety or the prevention of crime and disorder.
UK courts have previously stated that there is no cause of action in UK law for 'invasion of privacy', and that a breach of article eight of the European Convention on Human Rights merely allows a person to claim an 'adequate remedy'.
Anyone who feels their privacy has been breached in the UK may be better placed to claim for a misuse of confidential information. This falls under breach of confidence legislation and in essence allows a claimant to apply for an injunction when they feel they had a reasonable expectation of privacy.