A former chalk quarry operated from 1920 to 1975, the Lac Bleu was then purchased by the Departmental Council. In 1990, swimming was banned for health and safety reasons; the Lac Bleu was a reservoir of drinking water for neighbouring populations. In 2004, work was undertaken to restore the site to its natural state. As a result, today, the place has regained a certain tranquillity, with the return of the palmate newt and roe deer as proof of this.
Open : All year round except between 1 June and 15 September when the site is closed to the public