Blanchard was born in the Merlet neighborhood of St. Barths on 16 February 1896. She was born only 18 years after the former Swedish island of St. Barths was sold back to France. Blanchard was the last survivor of thirteen brothers and sisters.
Blanchard moved to Curaçao in May 1923, where she became a Catholic nun of the Congregation of Franciscan Sisters of Roosendaal on the island. She adopted the name Sister Cyria during her years with the order, but earned the nickname "Sweets" due to her treatment of others, according to Victorin Lurel, the President of the Regional Council of neighboring Guadeloupe. Other reports have indicated that Curaçaoan children called her "Douchy," which is derived from "Dushi" meaning "sweets" or "candy" in Papiamento, the creole language of Curaçao, because she worked as a sweet seller.
Blanchard remained with the Congregation of Franciscan Sisters of Roosendaal on Curaçao until August 1955, when she returned to Saint Barthélemy at the age of 60. She resided alone with her cat until she moved to a hospital nursing home in 1980 at the age of 84 due to declining health.
Blanchard was described as generally in good health during her later years, despite the loss of her eyesight and her ability to speak. She died in Saint Barth's on 4 November 2010, at the age of 114.