The lovely city park at the Square René-Viviani is one of the lesser-known public gardens in Paris. The well-manicured lawns, walkways, and mature trees providing shade for sitting benches welcome you here. A locust tree planted in 1601 and believed to be the oldest in Paris is the identity of Square René-Viviani. Even though supported by pillars, the tree is still robust. It is one of the parks where on-leash dogs are allowed.