Classifications, Inventories – NOGA General Classification of Economic Activities Frequently asked questions
Where can I find other economic classifications with correspondence tables?
Most international and national classifications (ISIC, PRODCOM; CPC; NAICS etc.) as well as correspondence tables for the various classifications are available at the following webpages:
European Union site: RAMON 
(EUROSTAT classification server)
United Nations site: UN Classification Registry
United States of America site: Correspondence table between the SIC (Standard Industrial Classification System) and the NAICS (North American Industry Classification System)