New Orleans in the early 1840s was the United States' third-largest city, the trade hub for the South, and had the largest concentration of French language speakers.

[6] Maurice and Elie followed after the summer sales, announcing to the press their planned “temporary absence,” and the purchase of 200 barrels of Kentucky whiskey for the San Francisco market.

)[15] In this instant city, Lazard Frères became one of the biggest retailers and wholesalers of English and French made goods, while Simon handled money trading and banking, a growing but informal part of the business.

[16] From the first they dealt in gold dust, in exchange for goods to miners, then as separate purchase of precious metal bullion (or, in reality, a crude dore bar), which they shipped back to France for assay and sales.

With Joseph Aron, Elie and Simon managed silver-bullion shipments between California and Paris and helped finance the Sutro Tunnel Company to bore four miles into the hill below the lode.

The closeness of the Lazard-Cahn-Weill-Aron family and primogenitor laws has been pointed to as one of the financial and social strengths of the Lazard Frères firm in the nineteenth century.

[32][33] The Lazard brothers came to California with the intention of working, saving, and returning home after becoming rich, a motive widely shared by immigrants of all backgrounds.

With the infusion of younger talent at the same time the international business continued to grow, the Lazards decided to permanently return home and establish headquarters in Paris.

[34] In 1861, after the completion of the transcontinental telegraph to San Francisco improved communication, thirty-three-year-old Simon left permanently for Paris; brother Elie followed five years later.

Close brother-in-law Alexandre Weill and the youngest brothers, S. Sylvain and David Cahn Lazard, tutored by Simon and Elie, remained in San Francisco as partners and local managers.

By the 1880s, the Lazard Frères offices in Paris, London, New York, and San Francisco, managed by family members, became one of the strongest international commercial and investment banks.

With David’s departure, Simon and Alexandre selected Marc Eugene Meyer, the first non-Lazard family member, to be in charge of the bank and Lazard Frères & Co.’s San Francisco office.

In coordination with the Paris and London offices and assisted by George Blumenthal (banker), he shaped Lazard Frères New York as a major speculator in railroad and utilities stocks and bonds as well as mastered the securities and precious-metals markets including sensational gold shipments to France.

They deal in the yellow metal in New York.” He added: “The sensations in Wall Street by these old Pacific coasters is in the matter of gold shipments — the bane of the stock bulls.”[46] Importantly, Lazard Frères & Co. were to orchestrate a financial empire that specialized in sending millions of dollars worth of gold and silver bullion from New York City to bolster France’s currency during the economic fluctuations of the 1880s and 1890s, while also profiting from the higher goldmarket prices paid in Europe.

The firm became known as one of “the greatest banking concerns of the world.” With his death in 1898, the San Francisco Chronicle remembered Simon Lazard among Californians and stated that he was ”highly esteemed by a large circle of friends on both continents for his liberal views, business ability and his lavish charities.”[47] Native of Lorraine, France, merchant of antebellum New Orleans, pioneer of the California gold rush, and, finally, international banker, Simon Lazard left an enduring legacy.