This chestnut's shape was cut into it by winegrowers. Its branches used to be lopped to make stakes for the vineyards, which is why it grew low, wide and twisted rather than tall, with bark that spirals up the trunk and a crown now eighteen metres across. It was once a lonely tree in the middle of a meadow. Then the town grew all around it, and La Celle-Saint-Cloud did something towns rarely do for a tree that is in the way: it redesigned a square, Place du Général Audran, specifically to show it off. The chestnut is the centrepiece, in a residential quarter called La Châtaigneraie, the chestnut grove. The European contest page, French Wikipedia and a Paris news site all give it about 330 years, and Le Parisien reported in 2022 that it went in under Louis XIV. That is an estimate repeated consistently, not a ring count, and nobody has published its girth. If you have measured it, tell us. In 2021 it was voted Île-de-France's tree of the year, then won France's national public vote, nominated by the heritage-tree association A.R.B.R.E.S. At the European final in 2022 it placed eighth of sixteen, with 28,119 votes. It does not stand in Viroflay. It stands in La Celle-Saint-Cloud, a five-minute walk from the station, direct on Transilien line L from Paris Saint-Lazare; from Viroflay the trip takes a change at Saint-Cloud.
Place du Général Audran, La Celle-Saint-Cloud, Yvelines (not Viroflay) You can recognise it by the low, wide, twisted crown, about 18 metres across, and the bark spiralling up its trunk. It stands as the centrepiece of Place du Général Audran, five minutes' walk from La Celle-Saint-Cloud station.
Free. Stands as 'the central piece of a square, redeveloped especially to showcase' it (contest page's own wording), Place du Général Audran, a public town square in the La Chataigneraie residential quarter of La Celle-Saint-Cloud. No gate, ticket or restriction mentioned in any of three independent sources.
DAY-TRIP ADDITION, genuinely in La Celle-Saint-Cloud, NOT Viroflay: the tree stands about 295m (a 4-5 minute walk) from Gare de La Celle-Saint-Cloud (Place Jean Mermoz), which is a direct stop on Transilien Line L, about 20-25 minutes from Paris Saint-Lazare with no change. From Viroflay (Rive Droite or Rive Gauche stations), also on Transilien lines through Saint-Cloud, the honest journey is one change at Saint-Cloud onto the La Celle-Saint-Cloud-bound branch of Line L; total journey is roughly 25-30 minutes door to door depending on the timetable, not a direct line. State this as a same-network day trip with one change, never as walking distance from Viroflay.