This reference for a preliminary ruling arose when the City of Lyon requested the administrator of the French national registry of greenhouse gas emission allowances to provide information on the sales of emissions allowances by the operators of the urban heating sites in 2005. The administrator refused to provide the information. The court found that while information on emissions allowance transactions is “environmental information” within the meaning of the Environmental Information Directive, the data could not be released because it had not reached the expiry of the five-year period and there were no overriding public interest served by the disclosure of such information which would outweigh the confidentiality of the information.

Source:
http://www.lse.ac.uk/GranthamInstitute/litigation/ville-de-lyon-v-caisse-des-depots-et-consignations-european-court-of-justice-2010/