According to the Guidelines, disclosure of personal data pursuant to foreign court proceedings must comply with applicable laws and treaties ratified by France, including the Hague Convention of March 19, 1970, which enables a contracting State to declare that it will not execute letters of request issued for the purpose of obtaining pre-trial discovery. In France, any judge receiving a letter of request from a foreign authority must verify that such a request is admissible under French law and, in particular, must refuse the request if it poses a threat to State sovereignty or security. In this respect, a French blocking statute (the July 27, 1968 Act) prohibits disclosure of any information of economic, commercial, industrial, financial or technical nature as part of foreign legal proceedings unless the disclosure complies with applicable treaties and laws. Any breach of this statute is punishable by imprisonment of six months and a fine of €18,000.
More information on these Guidelines can be found (in French) at www.legifrance.gouv.fr