When I was in Paris I really enjoyed seeing Rodin's gardens and Napoleon tomb. Then of course you have the beautiful architecture, personally I just enjoyed walking down the river, stopping in places for coffee and scoping out the scene. It might not be your thing, but my favorite place in Paris was the Basilique du Sacré Cœur or the Basilica of the Sacred Heart. Its a really beautiful place, especially underground in the catacombs with all the reliquaries. Its steps also give a great view of the Paris sky line and if I remember correctly it is surrounded by markets and what not.
Hope that helps.