Royal baby: Privacy warning at Kate and William's home
Letters warning the media not to harass the Duke and Duchess of Cambridge have been handed out by Norfolk police.
The royal couple returned to Anmer Hall, their village home on the Queen's Sandringham Estate, with newborn Princess Charlotte on Wednesday.
The letter, distributed in the village, asks the media to respect the couple's privacy after "a number of intrusions".
Kensington Palace said public interest had to be balanced with the couple's right to a "private family life".
The letter expressed the hope "acts of harassment and breaches of privacy" would cease.
Norfolk Police confirmed it had given out letters on behalf of the royal couple but would not comment further.
A Kensington Palace spokeswoman said the letter was "handed to individuals found operating on or around the Sandringham estate".
"The warm-hearted and understandable interest in the Royal Family and the Duke and Duchess of Cambridge needs to be balanced with their right to private family life - this is especially important for a family with very young children," she said.
"This is a letter given by police to individuals found operating on or around the Sandringham estate, including Anmer, on behalf of the royal household.
"It reminds them of their responsibilities and the rights of the estate. Media are encouraged to speak to royal communications for further guidance about where they can operate on this private estate."
The family had been staying at Kensington Palace since the birth of Princess Charlotte on Saturday but travelled to Norfolk on Wednesday.
The three-paragraph letter from the couple's communications secretary is being distributed outside Sandringham.
It says members of the Royal Family and their guests "have a more than reasonable expectation of privacy" while in the private estate.
"There have in the past been a number of intrusions into the privacy of the Royal Family which in the main have been as a result of professional photographers using long-distance lenses, not only to observe the Royal Family, but also to photograph them going about their activities on the estate," the letter says, adding that previous warnings given to photographers had helped the situation.
"The Sandringham Estate trusts that there will not be a need to take any further action other than bringing these points to your attention."
Clarence House declined to comment.
Anmer Hall, a Georgian mansion, is about two miles (3km) east of the Queen's residence and dates back to about 1800, although some parts are much older.
It has recently been refurbished and boasts a new kitchen and roof.
A garden room and quarters for the family's full-time nanny - who will also care for 21-month-old Prince George - was also created during the improvements.
The majority of the work was paid for by the Royal Family from private funds.