The motives behind the French intervention in Mexico had both a philosophical and economical component.

Let’s talk about the economic component: Mexico had just concluded the so-called War of Reform between the Liberals and Conservatives with the Liberals under Benito Juarez triumphant. Both sides had secured loans at exorbitant interest rates from European sources to finance their forces and Juarez’s government had little immediate means to service said loans. The Mexican government declared a two year moratorium on foreign debt payments in 1861. This moratorium provided the basis of a joint French, British and Spanish plan to seize the Veracruz customs house and use its proceeds to repay the loans. While the British and Spanish were in it for economic reasons, the French (or rather the Napoleon III) had far more ambitious designs for Mexico. This is where the philosophical component comes in.

The term Latin America, which we use so casually, was a term coined by the French to justify this adventure. The idea was that the Hispanophone and Lusophone nations of the Western Hemisphere had a common identity with each other and the French as they all spoke languages derived from Latin. Additionally, France and the ‘Latin’ nations all had a common Catholic bond. Napoleon III sought to unite Latin America and wield it as a counterweight against ‘Anglo-Saxon’ (and Protestant) America and Britain. The first step in Napoleon’s Latin project was a puppet regime in Mexico.

Once the British and Spanish found that the French intended to invade and occupy Mexico rather than merely collect debts, they abandoned the affair. Fighting was carried out by French troops (including the Foreign Legion) complemented by Austrian, Belgian and Egyptian/Sudanese and Mexican Conservative forces. After a stunning defeat of French forces at the Battle of Puebla (celebrated today in Mexico as Cinco de Mayo) in 1862, the invaders secured Mexico City in 1863 and sent Benito Juarez fleeing. Archduke Maximilian was inaugurated as Emperor of Mexico while Juarez continued a guerrilla war against the new regime.

As for how it turned out for France and Emperor Maximilian: this episode is sometimes referred to as the Mexican fiasco and Emperor Maximilian was executed by the victorious Juarez in 1867. The entire French enterprise became untenable once the American Civil War had ended. While the US government could do little while at war, it did supply arms to Juarez’s forces and it exerted diplomatic pressure on belligerents such as the Khedive of Egypt to ensure no further reinforcements would arrive to bolster Maximilian’s regime.