A couple writes their names on a padlock and locks it onto the bridges. They then throw the key into the Seine River as a symbol of their undying love. The love padlocks have been a phenomenon in other cities, such as Belgium and Japan. Some say the only way to break the seal of love brought on by this love lock act is to find the key and unlock the padlock. However, that’s nearly impossible, since the keys lie at the bottom of the river. Many brokenhearted individuals to return with bolt cutters to try to chop off the padlocks.
There are two bridges in Paris with the locks, so you must be careful which bridge you put your lock on because Pont des Arts is for your committed love, while Pont de l’Archevêché is for your lover.
This could be the explanation for why Pont de l’Archevêché is completely packed with locks, while Pont des Artshas has plenty of room.