The ConceptThe concept behind Velib' is relatively simple: swipe your credit card at any station around the city (situated roughly every 300 meters/984 feet) to rent a bike for a day or a week. You will pay a small flat fee for as many trips as you want throughout the day or week. If you end up biking for less than 30 minutes on a given trip, you will not be charged above and beyond the flat "subscription" fee. You don't have to return the bike to the station where you rented it-- you're free to drop it off at any Velib' point. This is one definite boon to the system compared against rental shops. The self-service stations are open 24 hours a day and seven days a week, which is another advantage.
Your credit card will be charged a deposit (currently €150, but this may change at any time) to ensure that the bike is properly returned and left in good condition. Make sure not to leave it unattended, even with a lock: thieves have powerful tools these days that can slice through even tough locks. Read more about the procedure for renting, using and returning Velib' bikes on the next page.
But...Is it Safe?I won't lie. Riding a bike in Paris can be stressful, and not ideal in terms of safety conditions. Traffic is often heavy, pedestrians don't always follow road crossing rules, and the city is full of one-way streets, roundabouts and busy intersections. I would advise only experienced urban cyclists to attempt to use the bike on busy roads, and only after consulting local traffic rules. For those of you unaccustomed to biking in traffic, you can still use Velib', but I'd strongly suggest that you head to park areas like the Bois de Boulogne or Bois de Vincennes and stay on cycle-only paths.
The other issue, as already mentioned, is the difficulty in procuring a helmet when you use Velib'. Some claim there's no substantial evidence for helmets protecting against serious injury or fatal accidents, but I'm a firm believer in their necessity.
Overall, Velib' can be a great way to get around the city for those who have some experience with urban biking. It's reasonably safe as long as you acquaint yourself with traffic rules, and don't assume that because you have the right of way, cars, pedestrians and other bikers will respect that. Ride defensively and alertly.