Located in the heart of Paris’s 5th arrondissement, just steps from the Seine and Notre-Dame, Square René Viviani is a peaceful, historic oasis. Established in 1928 on the grounds of an ancient cemetery linked to Saint‑Julien‑le‑Pauvre church, it reveals a setting rich with archaeological remnants and intriguing history.

One crowning feature of the square is the stately black locust, planted in 1601 by botanist Jean Robin. Known as the oldest tree in Paris, it now stands 15 m tall with a circumference exceeding 3 m, supported by protective braces. This living monument proudly spans over four centuries.

Scattered throughout are architectural fragments—balusters and capitals—rescued during 19th-century restoration work on Notre-Dame, creating a poetic dialogue between living wood and sculpted stone. A signature fountain by Georges Jeanclos, installed in 1995, evokes the medieval legend of Saint Julian, symbolizing redemption and hospitality. A nearby memorial for Jewish children deported between 1942–44 brings a quiet, poignant dimension to the site.

Throughout the seasons, the square transforms: in spring, pink hues from cherry and plum trees bloom early (mid to late March), offering a delicate floral display. Summer invites relaxation on lawns and benches shaded by foliage. In winter, a cozy Christmas market near Notre-Dame lights up the space with warmth and charm.

Visitors range from curious strollers and amateur photographers (especially framing Notre-Dame) to families seeking tranquility and lovers of hidden gems. Local lore whispers of an ancient well whose waters were once believed to have healing powers.

Practical info: open until around 8:30 pm (seasonal), wheelchair and stroller accessible, free all year except certain holidays, and conveniently located near Maubert‑Mutualité (line 10), Saint‑Michel (line 4), and Cluny‑La Sorbonne (line 10) metros.