Three things to do or see
Visit the Notre Dame:There is no entrance fee to visit the most famous church in France, and possibly all of Europe. The line moves very quickly, but just be sure to be keep quiet as you admire the stained glass windows and architecture.
Lock a 'love lock' to the Pont des Arts Bridge: This bridge links the Institute of Paris to the central square of the Louvre, over the River Seine. Recently, the chain link bridge has become a popular site for romantics, who buy a lock together, and lock the "love lock" to the bridge. Afterward, they throw the key into the river to seal their love. The lock costs money, but the memory is free.
Walk through the Jardin des Tuleries: Outside of the Louvre and stretching more than two miles, the garden offers statues and monuments among beautiful blooming flowers.