The service, defined as "as-you-wish rental of non-polluting vehicles" would require citizens to register and obtain a card. With that card, they would be able to take a vehicle at one of the hundreds of stations available and drop it at one near their destination. The deployment of this system is scheduled for several years, due to the complexity of the project (for instance, Barcelona's bicing system has been deployed in 4 months - and they're bikes).
The chosen vehicles for this service are not exclusively electric; "because they're not 100% ready", says the Delanoë, and will be defined as the system develops. Note that France is one country where electricity is relatively cheap compared to their neighbours, mainly because a lot of it comes from nuclear power.
This initiative is set into Paris' efforts to reduce pollution in the city. The Mayor already discarded a congestion charge scheme as in London but still is trying to accomplish his promise on reducing a 32 percent of air pollution before 2012.
[Source: La Tribune]