In the 5th arrondissement the oldest tree in Paris grows in the Square René Viviani. This gnarled black locust was planted in 1601. The tree is so old that it bends under the weight of its branches and relies on a cement structure for support. A team of gardeners care for it, removing dead wood and trimming the ivy that encircles it.
I've spent many peaceful hours in the square and in the adjacent medieval church, Saint-Julien-le-pauvre, one of the oldest buildings in the city.