I have traveled through Paris every way you can: bus, Métro, taxi, RER--I have even driven a car in Paris, which is exactly as terrifying as it sounds.
But when I visited last spring, I decided to try something new--for 96 hours, I'd only use human-powered transit to get around. That meant a lot of Vélib' bikes (which were scarier, but more fun, than driving that car) and, of course, walking. Over the course of one day, I walked and biked Paris from the Bois de Boulogne to the Bois de Vincennes, looping up and over Montmartre. It must have been 20 kilometers. I was sore after but happy, too. There'd been so much to see I'd not paid attention to my feet for a single minute.
There are many walking guides to Paris, but few as charmingly avuncular as Baxter's. He's an affable host and ready raconteur, and while this book does sketch out some walks, it's even more fun to read with your feet up in a chair, especially when Baxter gets to talking about cooking. He is incapable of being uninteresting (and if the stories he tells aren't enough just read his Amazon bio, which has enough adventure and twists for a dozen authors). Marchons!