Pont Rouge

The Pont Rouge was a bridge in Paris.

A wooden painted bridge, it connected the Île de la Cité with the Île Saint-Louis. Just beneath the bridge was an entrance to a tunnel network utilized by the local Assassin Brotherhood, that connected to the Sainte-Chapelle and the Café Théâtre.

Despite surviving the French Revolution, the Pont Rouge was soon destroyed and eventually replaced by the Pont Saint-Louis.

Reference

 * Assassin's Creed: Unity