The enormous complex La Défense on the outskirts of Paris will become 30 hectares of Wi-Fi coverage: The complex has 150,000 regular workers and 50,000 visitors a day. While it's a paid service, some information will be available for free, such as traffic details and transportation schedules. Costs weren't listed.
Update: An alert reader pointed out an earlier story on Wi-Fi Networking News pointing to a park in Lisbon that has a hot zone of 100 hectares. La Défense certainly will have vastly more regular users, but it doesn't cover more area.