alt Hacker NewsThere's no way France have no clause in its law everywhere that can be creatively interpreted to be used for that purpose. But that won't get enforced unless there will be a better option than Twitter that average Paris Metro employees understand; they would not be dumb, but they would not care. Average people today can barely grasp the concept of a password.
Surely it shouldn't be to difficult to come up with a sort of plugin-type approach like I've seen in various 'comments' sections on existing websites:
Simply embed the 'update' feed on a page in the existing website and have some kind of admin panel where employees can easily CRUD some updates.
I guess because even this would not be 'free', twitter ends up winning.