You'll never have to hop in a car while you're in Paris. In addition to taking the insanely reliable and frequent métro, you can explore the winding rues and impressive avenues on a vélib — the inexpensive public bikes offered on almost every corner. Paris is peppered with over 17,000 bicycles that you can pick up at one kiosk and return at another station near your destination; subscriptions are €1 per day or €5 per week, plus about €1 per half hour of use.
After you finish taking in the sites by bike, sign up for a professional walking tour. Paris Walks offers two-hour tours for about €12 on themes ranging from Medieval Paris, Parisian fashion, and "The Village of Montmarte."
Source: Flickr User notfrancois