Her mother Carole Middleton and sister Pippa have been photographed in recent days out shopping in London.
The Middletons have not made an official complaint to the PCC but the press regulator has sent an advisory to newspaper, magazine and broadcast editors to remind them of their obligations under the Editors’ Code of Practice.
A St James’s Palace spokesman said: “No formal PCC complaint has been made by the Middleton family about any breaches of the editors’ code.
“However, following some incidents of alleged harassment and pursuit by agencies and freelancers, the Middleton family, through the PCC, have sought to draw the attention of editors to their concerns.
“The Middleton family and St James’s Palace remain grateful to editors for their restraint and adherence to the code over the past few months.”
In the past Miss Middleton, Prince William’s fiancee, has turned to the press’s self-regulatory body when she has felt photographers have overstepped the mark.
A PCC spokesman would not discuss the details of the advisory, only saying it related to specific concerns.
He said: “In this case we can confirm the Middleton family did contact us through representatives and we did send out a private advisory notice on April 6 advising editors to be aware of their obligations under the editors’ code of practice.”