This preliminary ruling concerned a request by the Ville de Lyon to receive trading data relating to the names of holders of accounts for greenhouse gas emission allowances. The Court found that such trading data is not “environmental information” in the sense of the implementation of the Aarhus Convention within EU law and specifically Directive 2003/4 on public access to environmental information. The trading data is therefore not subject to a full right of access and a related obligation to disclose. The Court determined that the data comes exclusively under the specific rules governing public reporting and confidentiality which are contained in Directive 2003/87 and Regulation No 2216/2004. Consequently, access to such data can be more rigorously restricted and is not to be disclosed before a period of five years has elapsed following the year of completion of transactions relating to transfers of emission allowances.