To travel to the outskirts of Paris as well as fully experience the Arc de Triomphe round-a-bout, we rented a scooter for a day for 45€. I don't really recommend this for people who aren't experienced driving a two-wheel vehicle--I drive a Vespa regularly.
We rented from a nice place called Free Scoot, which has two offices in Paris (www.freescoot.com). Although the advertisement claims that they require proof of residence for 3 months, we just gave them our hotel name, address, and phone number, as well as my US driver's license. We got a 125 cc Piaggo, which had nice big wheels for stability and a good engine size for two people. They also gave us two pair of gloves, two helmets, and two locks.
It was a really fun way to travel through the city, and parking on the sidewalks was a breeze. They had a 1,600€ "hold" on my credit card for a security deposit, which they never charged on my card since I returned it intact. They also rent bicycles and electric scooters on a daily, weekly, and monthly basis.