Menhir de Bréau, Prehistoric standing stone in Montrevault-sur-Èvre, France.

The Menhir de Bréau is a solitary standing stone in the rural landscape of Maine-et-Loire, displaying characteristics of Neolithic construction. The monument sits on private property and is now protected as a historical site.

The stone dates to the Neolithic period and was erected by early people in this region. In 1990, it received official protection status as a registered historical monument.

Local tradition calls it La Pierre à vinaigre, the vinegar stone, and says it smells of vinegar; it is also known as the Pierre qui tourne du Moulin Neuf because it is said to turn at the twelve strokes of midnight. It stands near the left bank of the Èvre at Le Fief-Sauvin.

The site sits on private property, so access is restricted and requires permission from the owner. Visitors should make inquiries and ask the landowner before attempting to view the monument.

Local tradition holds that the stone turns at the twelve strokes of midnight, and that it smells of vinegar — hence its name La Pierre à vinaigre. It is also called Pierre qui tourne du Moulin Neuf. An old excavation reportedly found a setting of Roman-era bricks beneath it.