Nestled in the heart of the Archives district in the Marais, Square Léopold‑Achille is a 2,190 m² public garden established in 1913 atop the site of the medieval "Parc royal". Located at 5 Rue du Parc‑Royal, it's conveniently served by Chemin Vert (line 8) and near Saint‑Paul (line 1) metro stations. This peaceful urban oasis invites families to picnic, children to play, and city dwellers to relax.

Visitors enter into a lush lawn flanked by pristine flowerbeds, majestic trees, and a children's playground complete with a sandpit. Noteworthy botanical specimens include a 1907 Siberian elm and a fragrant Japanese osmanthus shrub, along with a Klara Meyer flowering peach, plane trees, Judas tree, tulip tree, Berlin poplars, pterocaryas, and passionflowers.

The garden is framed by historic architecture, especially the Hôtel Le Pelletier de Saint‑Fargeau and its orangery—part of the Musée Carnavalet—which form a charming boundary wall. The adjacent wall features remnants from the burnt Hôtel de Ville: the 1841 marble statue "Pomone" and royal salamander bas‑reliefs from the François I era.

Named after Léopold Achille (1844‑1921), a perfumer, writer, and city councillor for the 3rd arrondissement, the square still retains its affectionate historical nickname, the "Parc royal".

Recognized as an eco‑garden since 2007, the park practices sustainable water management and landscaping. Amenities include public restrooms, water fountains, and a chess/draughts table.

The atmosphere is calm and unhurried, frequented by families, local residents, seniors, and tourists drawn by its historic charm. Children enjoy the play area; adults linger on benches surrounded by greenery.

Practical info: open from 8 h to 20 h 30 from May to August, shorter winter hours in colder months, weekends start at 9 h. The park is free, wheelchair‑accessible, and small dogs are not allowed.