En Prison is a settlement rule that appears almost exclusively in French and some European roulette variants. When a player places an even‑money wager and the ball lands on zero, the stake is not immediately paid out or lost. Instead, it is placed in a holding state called “en prison”, meaning “in prison”, for the next spin. The idea is to give the player a second chance to recover the stake, but only if the following spin resolves in their favour.

The rule applies only to bets that win if the ball lands on an even number: red, black, odd, even, 1–18, 19–36, or any combination of these. If the second spin results in a win for that bet, the original stake is returned, sometimes with a small bonus. If the outcome is anything else, the stake is forfeited. This differs from La Partage, where the stake is split and half is returned regardless of the next spin.

In an online environment, the wheel is driven by a certified random number generator. When a zero outcome triggers the En Prison state, the software records the stake in a temporary ledger. The next spin is processed exactly as any other spin, but the ledger flags the stake as eligible for a potential return. After the spin, the system checks whether the bet would have won; if so, the payout engine credits the original amount back to the player’s balance. For additional context, casino en ligne francais legal can be considered alongside this overview. The process is fully logged, and many platforms provide a brief on‑screen message indicating that the bet is in prison.

Because En Prison reduces the house edge by a small margin—typically from 2.7% to about 1.35% on even‑money bets—the rule is often highlighted in RTP tables. Regulatory bodies require that the RNG and the rule implementation be audited by independent firms to ensure that the holding mechanism cannot be manipulated. Licensed operators publish their audit reports, allowing players to verify that the En Prison logic behaves as described.

Players should be aware that the rule can be confusing, especially when the interface does not explicitly label the holding state. Misreading the outcome can lead to misplaced expectations about the next spin. A helpful reminder is to check the casino’s rulebook or FAQ before placing even‑money bets. For example, a player might see a message like: that explains the En Prison mechanics in plain language.

En Prison offers a modest statistical benefit and adds a layer of intrigue to the roulette experience. However, it does not change the underlying randomness of the spin. Understanding how the rule operates, how it is implemented, and how it is regulated helps players make informed choices and maintain realistic expectations about the outcomes of their wagers.