Okay you’re in Paris, so I guess you should see some sights too? If you haven’t already, walk through Place des Vosges (pst. No. 6 was Victor Hugo’s old pad, you know from Les Mis and The Hunchback of Notre Dame), take a fun picture at Hotel Sully, cross over Pont Marie for a scoop (or 2) of Paris’ famous Berthillon ice cream.
Now head over Pont Saint-Louis (which links the two islands) for your up close look at Notre Dame which is free to enter. But, if you plan on climbing the 387 stairs to the towers, you will need to purchase a ticket for €8.50 or €6.00 for a visit to the crypt. While you are visiting Notre Dame, take a peak at Point Zero, the absolute center point of the city from where everything is measured).
Here on Île de la Cité, you also have Saint Chapelle. Built to house precious Christian relics including the Crown of Thorns (currently housed in the cathedral treasury of Notre Dame), today people line up around the corner to peak inside this 13th century gothic church as it has the world's largest collection of original stained glass windows.
Next is the Conciergerie, a medieval royal palace turned into a revolutionary tribunal which was used to house high value prisoners such as Marie Antoinette.
If you want a nice picture, walk down Pont au Change and turn back around to capture The Conciergerie. Walk across Pont Saint-Michel to start exploring Rive Gauche, Paris’ Left Bank.
Pst. There are many ways you can get to Jardin des Plantes, your next stop on your Day. But, if you'd like a suggestion, we love walking along the Seine through Jardin Tino Rossi, an open air museum that ends up right in the garden!