Chapelle Saint-Louis

If you've ever walked down rue Victor-Hugo, you may have come across this pretty 17th-century chapel with its red brickwork... The current retirement home at the end of the street was built on the site of a former hospital founded by Mme de Combalet, niece of Richelieu and first Duchess of Aiguillon, at the same time as this adjoining chapel.
Have you noticed this detail on its façade? It's adorned with a carved scallop shell, testimony to the passage of the famous pilgrims.