A 3 hour afternoon stroll took me (I didn't have a plan) from Place d'Italie, where I'm staying, up Gobelins to Mouffetard, left on Clovis and right at St Etienne du Mont down the Mont Ste Genevieve to the Île de la Cité, where I circumambulated Notre Dame, crossing the tip of Île St Louis to the right bank and back (after much-needed caffeination) across Île St Louis along Cardinal Lemoine, Monge and Gobelins. 13th, 5th, 4th!
