The Grande Armée was the henchmen of Napoleon Bonaparte. They were the henchmen of one of the secondary antagonists of Night at the Museum: Battle of the Smithsonian.
Although, Napoleon don’t really see where the point is, but he understand they will be given a part of the world in exchange of helping Kahmunrah. They joined the Egyptian Pharaoh when Napoleon agreed to join.
Napoleon leads them and captures Larry Daley in the National Gallery of Art and brings him to Kahmunrah. When Napoleon later sees him through a telescope with Amelia Earhart crossing a park. Kahmunrah, thinking they are trying to flee, sends his forces against them. They find Larry and Amelia in the Air & Space Museum, but they fail in the pursuit this time.
They later battle against Larry's friends along with Al Capone's gangsters and Ivan's Stretsly.
The Grande Armmée was the French Army commanded by Napoleon, making their debut in the Napolenoic Wars. Its largest size was 680,000 troops. From 1805 to 1809, the Grande Armée, under Napoleon's command, scored a streak of millitary victories that gave the France dominant power over the European continent. A huge chunk of Europe was either controlled by or forced to obey France. They also successfully defended France from other European powers. One of their most notable victories was at Austerliz.
The army suffered great losses after Napoleon's disastrous invasion of Russia. Its last battle was at Waterloo.