Nothing wrong with either suggestion, but Marc's is more Campo di Fiori, JoAnn's more Via Veneto. ;)
I would recommend a three star hotel in the 5th or 6th arrondissement (Latin Quarter/St. Germaine) to get more of a real feel for the city. Make sure you're within walking distance of a metro stop as you can get to anything without having to be around the corner from a monument. Better to be in a fun neighborhood! Mais oui?
