The Tourelle de la Plate, also known as Petite Vieille (Little Old Woman) is a lighthouse in the dangerous strait Raz de Sein, off the northwest coast of France, belonging to the departement of Finistère in the region of Brittany.
Its companion light, La Vieille, is 260 metres to the north-east.
The octagonal turret is supported on a cylindrical base, these two parts being mounted on reinforced concrete.
On December 4, 1896, a violent storm broke over the tower which was "beheaded".
On August 31, 1911, a permanent green fixed light, burning oil, was installed.