MollyTroubletail wrote:
How about in a university library? There should be a lot of single girls there.
The issue with that is that, typically, one is not expected to speak in a library. ^ _ ^
That said, the line for la Bibliothèque Ste.-Geneviève (près du Panthéon; RER B - Luxembourg) is usually pretty long, and you could more than likely chat up some beautiful women there while waiting to get in to the main space (when I was there, wait time was typically an hour or more). You could also meet gals at the BnF, which has quite a few non-reading areas for talking.
As for cafés/bookstores, there's a pretty good anime bar somewhere in the Latin Quarter, and the people who frequent Shakespeare and Co. usually are pretty intelligent, though these are generally more touristy areas I suppose.