I subscribed to the bike-share programme, Velib, a couple days ago and have used it twice so far, with great joy. The first time was on the right bank, where there are two stations, under two bridges. It took us a while to follow the instructions and get a bike--and we weren't the only ones: we thought we'd get some help from a young American-British couple, but they were swearing at the computer system as gustily as we were. But anyway we got a bike, the quai, which was closed to automobile traffic last year, was fairly empty, it being a weekday, and I went to the bassin de l'arsenal and back a couple times while Michel walked.
Today we got two bikes and were on the left bank where you can ride from (almost) the Pont des Arts to the depths of the 15th arrondissement, way past the Eiffel Tower. Today being Sunday there was lots of foot, skateboard, scooter and other traffic, but it was still lovely to get from one end of Paris to another so easily and with the Seine flowing alongside.
The quais on both banks are being fixed up, with games, cafes, rock-climbing for kids, lounge chairs, fruit trees. I prefer the right bank. It runs through less upscale neighbourhoods and its denizens feel ordinary-er.