Jules Guex (1833-1918) was a Swiss national who was caught in the German siege of Paris from September 1870 to January 1871. He and his wife, Louise Adele Begue Guex (1839-1884) helped to organize a Swiss ambulance in the Collège Chaptal (now the Lycée Chaptal). His activities in rescuing the wounded enabled him to view the movements of both French and Prussian troops.

Jean Jules Samuel Guex was born to Jeanne Françoise Rémy (1810-1894) and Pierre Alexander Guex (1808-1864) in La Tour-de-Peilz, Switzerland. His father was a banker, the director in Vevey of the Palézieux bank. Jules Guex became a banker of the Lombard & Odier in Geneva.

In 1861 he married Louise Begue in Paris, France. In 1844, her sister, Gabrielle Camille Begue (1824-1905) married James Irenee Bidermann (1817-1890), the grandson of Eleuthère Irénée du Pont (1771-1834), the founder of the gunpowder manufacturing company, E.I. du Pont de Nemours & Co.

Guex supported and advised from 1875 until her death, Lydie Hocart (1846-1917), founder and director of an orphanage "la maison des enfants" or the Children's House. He was even director of this work in 1917 and 1918. His son Henri Guex (1863-1944), pastor, assumed the presidency of the work upon the death of his father until 1919.