On June 7, 1863, French forces captured Mexico City. The only thing most of us recognize that came out of this French-Mexican conflict is Cinco de Mayo. Cinco de Mayo, however, commemorates the Mexican army's victory over French troops at the Battle of Puebla a year earlier, on May 5, 1862.
Do you want to know more about the French in Mexico and why Napolean III sent them there? See books in the library's collection. And, see newspaper accounts in the Chicago Tribune and The New York Times (search for "French Invasion of Mexico).