mod_rewrite can access domain?

Hi,

Hi have a client that has 2 different domain names pointing to the same website, but one going to the french section and the other to the english section. The problem is, both websites are on the same hosting. In fact they are the same php pages but with a variable that changes for each language.

for example:
www.frenchdomain.com has to become www.frenchdomain.com/index.php?l=f

and www.englishdomain.com has to become www.englishdomain.com/index.php?l=e

Both domain names are supposed to point to the same IP, so theorically they display the same pages.

I tried to rewrite using mod_rewrite, but it seems that the module cannot rewrite based on the the domain name part of the url. Am I wrong? If not, any suggestions?

Thank you for your help.