Léopold Louis-Dreyfus

French investor and businessman, founder of the Louis Dreyfus Group, and patriarch of the Louis-Dreyfus family. Louis-Dreyfus also served as Consul-General for the Kingdom of Romania in Paris. The French government awarded him the title Commander of the Legion of Honour in 1912. By the early 20th century, the Louis-Dreyfus family was described as one of the "five great fortunes of France".

He was born to a Jewish family. His parents were Louis Lemlé Dreyfus (1798), a farmer, and Jeannette Victoire (née Hildenfinger; 1803–1837). As a youth, the younger Dreyfus made frequent trips to nearby Basel, Switzerland, delivering grain for sale from the family farm. In 1851, he began trading wheat from neighbouring farms. He founded a company under his father's name, as he was too young to use his own. The younger Dreyfus later changed his surname to Louis-Dreyfus, but kept the company name without the hyphen.

In 1858, after rapid growth, he moved the company to Berne, Switzerland, where it expanded its operations throughout Europe by purchasing grain from the "breadbaskets" of Eastern Europe and transporting it to the hungry markets in Western Europe. In 1864, the company moved to Zurich, Switzerland and in 1872, after the Franco-Prussian War when France ceded Alsace to Germany, Louis Dreyfus chose French citizenship. He moved to the shipping port of Marseille and by 1875 had moved his company's headquarters to Paris.

By 1900, the Louis Dreyfus Group was the world's largest grain trader. In 1905, the Banque Louis-Dreyfus was founded to help finance the company’s operations in grain markets. Thereafter, the company expanded internationally: in 1909, it opened an office in Duluth, Minnesota and began exporting durum wheat; in 1911, it started trading cotton in Brazil; and in 1913, it set up operations in Melbourne, Australia.

Léopold Louis-Dreyfus died on 9 April 1915, aged 82, in Paris, turning over the family company to sons Louis and Charles.