(Ask me where we had breakfast.)
The fountain in Pl. St-Michel is right there as you come out of the METRO at the Notre Dame/St-Michel stop on the RER B-line.  This was one of the first sights we saw in Paris when we arrived that Sunday morning.
Right across the street (to the right of the Parisiennes in the picture) is a "Gilbert Jeune -- Livres Scolaires" which I presume is the local equivalent of Barnes&Noble.  They also sell "records, CDs, et K7s".  It took me two days to figure out what a K7 was...  Click here to find out what a K7 is.