A short-term Louisiana militia command formed for defense of New Orleans in mid-February of 1862. Doubtless many of them found their way into military service of the Federal government following the surrender of New Orleans.
http://www.acadiansingray.com/3rd%20Regt.%20(G.F.),%20European%20Brig.%20Mil.htm

http://history-sites.com/cgi-bin/bbs53x/lacwmb/webbbs_config.pl?noframes;read=10920

There's also a recelty-published eighty-eight page booklet on the "European Brigade" --
http://www.authorhouse.com/Bookstore/BookDetail.aspx?Book=261761