The main difference between the Régiment de Cuisine and a regular Shokugeki is in the format of the challenge; rather than a single cooking duel between two parties, a Régiment de Cuisine consists of multiple battles.
Teams are generally equal in number, however, there have been instances of opposing factions having different member counts. Jōichirō Saiba, for example, single-handedly took on a team of 50 3rd year students in his 2nd year and won by himself.
In each round, a set number of members from each team face off against each other in simultaneous 1-on-1 duels. Teams are allowed to choose who battles in each round. Additionally, team members on the field are allowed to assist in their teammates' cooking during the battle.
Who faces who is randomized from the chefs that were chosen to battle in a respective round. Themes are also randomly chosen by having one of the contestants for a duel draw from a lottery box.
Ingredients are supplied in a large storage unit that contains a wide variety of ingredients, ranging from (possibly) a live caiman to store-bought kiri mochi. This is likely due to the fact that themes are chosen on the spot, so participants have little to no time to prepare a dish and secure ingredients. Though, contestants may also use any ingredients they brought, should they have the forethought.
If a team member loses their duel, they are permanently removed from the group and cannot face off in any subsequent battles. Alternatively, a team member who wins will stay in the competition and can then compete in a later round. Once one side has lost all of their members, the opposing side wins the Régiment de Cuisine.
Stipulations and conditions to set up a Régiment de Cuisine are the exact same as a Shokugeki, and like a Shokugeki, a Régiment de Cuisine is meant to solve a dispute on campus and can be initiated by anyone.