My train arrives at Gare de Lyon, and I need to get to Vaneau (Line 10). Map says that Gare de Lyon is connected to Gare Austerlitz (across the Seine) by "liaison urbaine." What is that? Thanks.
I believe "liaison urbaine" is a fancy way of saying: "walk". It's an 8 minute walk between Gare de Lyon and Gare d'Austerlitz across Pont de Charles de Gaulle.
There are several buses (24, 57, 61, 91) that will go between Gare de Lyon and Gare d'Austerlitz if walking isn't an option. Travel time is about the same or a bit longer.