The Paris Mayor’s office bike rental page has shows an up-to-date listing, including a map where to find the rental offices.
We rented bikes, took them on the train for a day trip to Moret-sur-Loing, south of Fontainebleau. I can recommend:
Paris à vélo, c’est sympa (guided tours, rentals and sales)
22, rue Alphonse Baudin (telephone: 01 48 87 60 01)
Bike tours and bike rental
Paris Bike Tour
