The Church of Saint-Germain-des-Prés is the oldest existing church in Paris, located at 3 Place Saint-Germain des Prés, 75006 Paris, France. Originally founded as a Benedictine abbey in 558 AD by Childebert I, son of Clovis, it has played a central role in Parisian religious, intellectual, and cultural life for over 1,400 years.
 
interesting facts....
The church houses the tomb of philosopher René Descartes and use to hold a part of the cross Jesus was crucified on.