On the morning of April 3, 1803, in the Valley of the Loue near Ornans, about 20 km from Besançon, Cecile Mille (October 16, 1789-July 13, 1835), saw "a beautiful, tall lady dressed in white, accompanied by four little girls also wearing white clothes, each carrying a lit candle. This beautiful lady continued walking all the way to the 'Oak of Our Lady'"...
On August 15, 1803, Cecile and a few others saw two "lights" that were coming out of the Oak of Our Lady near the lower branches. A closer inspection led to the discovery of a 19 cm clay statue of the Virgin with Child, dating from the 17th century.
A chapel was built by the oak tree, which was consecrated on August 3, 1869 by Archbishop Mathieu.
Cf. René LAURENTIN and Patrick SBALCHIERO, Dictionnaire encyclopédique des apparitions de la Vierge. Fayard, Paris 2007.