The rules applicable to privacy of public figures vary from one country to another. The European Court of Human Rights (ECHR) clarified last June the interaction between Article 8 (right of privacy) and Article 10 (right to freedom of expression) of the European Convention on Human Rights.
The case involved publication of pictures of Princess Caroline Von Hanover in different German newspapers. The photographs in question represented the Princess in her day-to day life.
In reaching its conclusion the ECHR held that, although Princess Caroline Van Hanover was a well known public person, she did not exercise any official function. The Court therefore decided that the general public did not have a legitimate interest in knowing about the Princess’ private life, even if she appeared in public places and was likely to be recognised by the public. The court therefore considered that there was a breach of Article 8 of the European Convention on Human Rights.
the decision of the ECHR is accessible here