Nicole studied medicine in Paris from 1896 and in 1899 married André Girard, whose family had a vineyard that produced Champagne in Saumur. They had one son – Etienne. Nicole worked with her husband producing champagne until they divorced in 1903 and Nicole went back to studying medicine, writing her Thesis on carcinogenic toxins. In 1910, she represented France at the Congress of Vienna with Albert Robin. In 1914 Nicole opened a TB clinic in Beajon, researching into cancer as well as TB.
When the First World War broke out, Nicole volunteered her services as a doctor to the French Army, using the name Dr. Girard-Mangin and initially worked at the Beaujon Hospital in Paris. She was called up - possibly due to a civil servant mistaking the name Girard for that of a man - and the authorities were startled to find a woman doctor. As this was the first instance of a woman doctor in the French Army, the problem of her uniform arose. Nicole was posted to the quiet town of Verdun, where she was put was in charge of Typhoid patients.
Verdun did not remain a peaceful outpost for long! On 21st February 1916 when Verdun came under heavy shelling, Nicole was wounded slightly in the face but headed the convoy taking the wounded to safety. In December 1916, Nicole was promoted to the rank of Major and was posted to Paris where she was in charge of the Edith Cavell Hospital in rue Desnouettes.
After the war, Nicole joined the Red Cross and travelled around giving talks on the role of women during the First World War. She died in Paris of an overdose on 6th June 1919, having never received any medals, awards or recognition for her war service.