Help with RewrietRule and language folders

[Jazztronik]

I need to manage languages in a website, and this is the structure of the URL:

www.mysite.com/en/displaylist
www.mysite.com/fr/displaylist

I want to rewrite the URL so that the language is not in the URL path, and sending it as a GET variable, like this:

www.mysite.com/displaylist?lang=en

This is the RewriteRule I made, but it doesn't work:

RewriteRule ^(es|en|fr|de|it|ru)/(.*) $2?lang=$1 [L]

Any help appreciated.