Lawyers representing Prince William's girlfriend have written to newspaper and magazine editors expressing concerns over her privacy.
Miss Middleton and Prince William met at university
They are asking them not to publish pictures taken by the paparazzi as Kate Middleton goes about her everyday life.
Miss Middleton met Prince William while they were both undergraduates at St Andrew's University.
Some publications have recently carried a photograph of the 23-year-old staring out of the window on a London bus.
According to BBC Royal correspondent Peter Hunt, Miss Middleton's friends say she is followed by photographers day and night. But they argue she is a private individual, who has not courted publicity.
Ms Middleton's lawyers, Harbottle and Lewis, who also represent the Prince of Wales, said the behaviour of some photographers could amount to a breach of the Press Complaints Commission code.
Its letter also details issues they were unhappy about and stresses the need to protect Miss Middleton's privacy and that of her family.
"We are aware of the letter, which pointed out some concerns about the behaviour of the paparazzi, the purchase of pictures and the need to protect her privacy, but it's a matter for Miss Middleton's lawyers," said a Clarence House spokesman.
The PCC confirmed it was sent a copy of the letter but said it had not received a formal complaint.