I have absolutely no experience of this service or knowledge of it beyond what is posted on the website.
Here is a rough translation of this
Paris Portail page:
The Paris-Wifi Pass
The Paris Wif-Fi Pass is a new service established by the City of Paris and the Ile de France region. It allows you free wireless, high-speed internet connection. It is open to everyone: Parisiens, French residents and visitors to Paris.
To use it, go to one of the 260 municipal sites equipped with one or more Paris Wi-Fi Pass hotspots: park or garden, arrondissement headquarters, library or museum of the City of Paris.
How to connect with the Paris Wi-Fi Pass?
1. Locate the place bearing the logo Paris Wi-Fi. This indicates that you are in the area of a Paris Wi-Fi hotspot.
2. Turn on your Wi-Fi equipment.
3. Select the Orange network.
4. Launch your Internet browser as usual and type any website address (for example:
http://www.paris.fr).
5. Select your pass Paris wi-fi 2h offered by the mairie of Paris et the Region Ile de France.
6. After that you can surf for free on the internet, send and receive emails, etc., without needing to connect by other means!
Important reminders:
Attention! Remember to fully charge your batteries in advance: electricity is not furnished by the Pass Paris Wi-Fi.
The Pass Paris Wi-Fi is accessible during the open hours of the municipal sites so equipped. To find out the schedules of these sites, enquire at the reception desk of each of them. In order to facilitate the evacuation of these sites at closing time, please obey the instructions of the municipal employees.