Paris is only expensive if you don't do your research...we go there regularly and it's much cheaper than Dublin (with the possible exception of drinks in pubs)
For a first trip I'd actually say skip the Louvre if you haven't been to Paris before...would do the Eiffel Tower, Bateaux Mouches, The Trocadero, Notre Dame, Sacre Coeur, Pere La Chaise....a stroll around the Latin Quarter...so much to do. Night shows...not a Paris must in my opinion, so much more to see and do with your money.
However, Paris in November is FREEZING, a horrible damp cold (I've been there three of the past four Novembers...anniversary). So it depends on what you want in the break.