Looks like JCDecaux is getting a little sloppy in Paris. As reported by the U.K.'s Times Online, "[Paris mayor] Delanöe is threatening penalties against JCDecaux, the advertising firm that operates [Vélib'] because so many are out of service or in disrepair from overuse and vandalism. Decaux, which has been given a monopoly on advertising space in return for the bicycle system, has been unable so far to ease the problem of saturation in Paris when commuters arrive in the morning. The lack of docking space deters many Parisians from picking up Vélibs for the ride to work."
Maintenance and logistics are large operational issues, especially in the largest of bike-sharing programs. I'm sure JCDecaux can get this back on track soon.