The French even-money rules that almost halve your house edge, when the casino is honest about offering them.
La Partage and En Prison
Annabel Cavendish
Editor · 14 May 2026
Why the House Edge Exists on Even-Money Bets
Start with the arithmetic, because it makes the rules legible.
On a European single-zero wheel, when you bet on red, you win if any of the 18 red numbers comes up. You lose if any of the 18 black numbers comes up. The zero is the mechanism. There are 37 pockets and you're being paid as though there are 36. That one extra pocket, zero, is the entire source of the 2.703% house edge on even-money bets. On those bets, it lands against you roughly one time in 37.
La Partage changes what happens when zero lands. Instead of losing your entire stake, you receive half of it back. The name is French for "the sharing." The arithmetic is direct: your expected loss on an even-money La Partage bet is 0.5 divided by 37, which is 1.351%. Exactly half the standard European edge. As Wikipedia's En Prison article confirms, La Partage on even-money bets produces a house edge of 1.35% and an RTP of 98.65%.
En Prison does something slightly different. When zero lands, your stake is locked, imprisoned, for the next spin. If your bet wins on that spin, you receive your stake back with no profit. If it loses, the casino keeps it. The mathematics of En Prison produces an edge of approximately 1.39%, marginally worse than La Partage because the imprisoned bet rides at the full 2.70% wheel odds for the recovery spin, including the possibility of zero landing again and ending the imprisonment. La Partage's immediate half-return is fractionally better in expected value terms. The difference is small enough that you'd need a large number of sessions to notice it, but the direction is clear.
The Critical Restriction: Even-Money Bets Only
Here is the thing I most need you to hear clearly about both rules: they apply exclusively to even-money bets. Red and black, odd and even, low and high, the first and second eighteens. They do not apply to dozens. They do not apply to columns. They do not apply to streets, corners, splits, or straight-ups.
This is the most common misconception among players who move to a French table thinking they're now paying 1.35% on everything they bet. They're not. A player who moves to a French table and then bets a dozen is paying the standard European rate of 2.70% on that bet, regardless of the French designation. The rule exists because even-money bets are the only roulette wagers structured as a clean binary outcome, and the zero is the pure mechanism of house advantage on those bets. La Partage halves the impact of the zero only on those bets.
As PokerStars UK explains in their La Partage and En Prison overview, the distinction between which bets are and aren't covered is essential before you approach a French table.
Where You Actually Find These Rules
In Monaco, the picture is clear. According to the Casino de Monte-Carlo's French roulette page, genuine French roulette is offered exclusively at the Casino de Monte-Carlo within the SBM group, with a minimum of €5 and a maximum of €2,000 per bet. At that table, when zero lands, the player may choose between La Partage and En Prison; both options are available. At the English roulette tables at both the Casino de Monte-Carlo and Casino Cafe de Paris, zero automatically defaults to En Prison on all even-money bets. French rules at the original French venue are the historical norm.
In London, the situation is considerably less generous. The UKGC does not mandate La Partage. It is entirely a commercial choice, and most UK floors, even those running single-zero European wheels, don't offer it. The confirmed exception is Aspers at Westfield Stratford, whose European tables apply La Partage publicly, reducing the even-money edge to 1.35%. For a serious player who cares about edge and doesn't require a Mayfair postcode, that matters significantly.
Online, the rules are consistently available because they're operationally straightforward to implement. Evolution's French Roulette Gold and Auto Roulette La Partage apply La Partage on even-money bets as standard. Playtech's French Roulette table does the same. Pragmatic Play added a live French Roulette table with La Partage to its catalogue in mid-2025. On these tables, the rule is automatic: zero lands, half your even-money stake returns, no theatre required.
En Prison is essentially unavailable at online live dealer tables because it's operationally impractical when multiple players at the same table have bets at different stages of imprisonment. La Partage is the universal online standard because it's a one-step settlement.
Why La Partage Isn't Universally Offered
The reason La Partage isn't universally offered at UK land-based casinos comes down to margin. It halves the casino's theoretical revenue on even-money bets. No regulation requires it, and most operators don't volunteer to halve their take. The rule is only available where explicitly labelled as French Roulette, and UK floors run far more European tables than French ones.
The "Mayfair rule" framing has some historical basis: London's high-roller rooms traditionally ran French tables for serious players, and La Partage was part of what made those rooms more appealing to sophisticated gamblers than provincial club roulette. That tradition has eroded in practice. Even at Mayfair addresses, standard European-wheel tables now outnumber French tables, and La Partage at a specific Mayfair venue remains unverified without calling ahead.
The Annual Cost of Getting the Wrong Table
At £100 per bet, 50 bets per hour, 100 hours of play across a year: total action is £500,000. Expected loss at a standard European table is £500,000 times 2.703%, or £13,500. Expected loss at a French La Partage table is £500,000 times 1.351%, or £6,750. The annual saving from finding a La Partage table for your even-money session play: exactly £6,750. That's not trivial. It is worth asking.
<aside> Second-zero rules under En Prison vary by venue. Most online tables: a second zero loses the imprisoned stake immediately, one imprisonment only. Traditional French land-based tables may allow a second imprisonment or apply La Partage to the imprisoned stake. The Casino de Monte-Carlo English roulette tables default to En Prison with a second zero losing the stake entirely. Check the specific rules before assuming you know what happens to your imprisoned bet. </aside>
Key numbers
Variant
House edge (even-money)
House edge (all other bets)
RTP (even-money)
European single-zero
2.70%
2.70%
97.30%
French: La Partage
1.35%
2.70%
98.65%
French: En Prison
~1.39%
2.70%
~98.61%
American double-zero
5.26%
5.26%
94.74%
Annual saving (even-money bets, La Partage vs European)
Assumptions
£100/bet, 50 bets/hr, 100 hrs/year = £500,000 total action
Welcome to the lesson on La Partage and En Prison.
I'm Annabel, and these are the two French roulette rules that genuinely do make a mathematical difference to what you're paying at the table.
Not a large difference, but a real and calculable one, and knowing when they apply, and when they emphatically don't, is one of the more practically useful pieces of knowledge in this series.
Let me start with why the house edge exists on even-money bets.
On a European single-zero wheel, when you bet on red, you win if any of the eighteen red numbers comes up.
You lose if any of the eighteen black numbers comes up.
The zero is the point.
There are thirty-seven pockets and you're being paid as though there are thirty-six.
That one extra pocket, zero, is the entire source of the two point seven percent house edge.
On even-money bets, it lands against you roughly one time in thirty-seven.
La Partage changes what happens when zero lands.
Instead of losing your entire stake, you receive half of it back.
The name is French for "the sharing." The arithmetic is straightforward: your expected loss on an even-money La Partage bet is zero point five divided by thirty-seven, which is one point three five percent.
Exactly half the standard European edge.
En Prison does something slightly different.
When zero lands, your stake is locked, imprisoned, for the next spin.
If your bet wins on that spin, you receive your stake back with no profit.
If it loses, the casino keeps it.
The mathematics of En Prison produces an edge of approximately one point three nine percent, marginally worse than La Partage because the imprisoned bet rides at the full two point seven percent wheel odds, including the possibility of hitting zero again.
La Partage is unambiguously better in expected value terms.
The difference is small enough that you'd need a large number of sessions to notice it, but the direction is clear.
Here is the thing I most need you to know about both rules: they apply exclusively to even-money bets.
Red and black, odd and even, low and high, the first and second eighteen.
They do not apply to dozens.
They do not apply to columns.
They do not apply to street bets, corners, splits, or straight-ups.
This is the most common misconception among players who move to a French table thinking they are now paying one point three five percent on all bets.
They are paying one point three five percent on even-money outside bets and two point seven percent on everything else.
A player who moves to a French table and then bets a dozen is paying the standard European rate, regardless of the French designation.
The rule exists because even-money bets are the only roulette wagers structured as a clean binary outcome, and the zero is the pure mechanism of house advantage on those bets.
The rule halves the impact of the zero only on those bets.
Now: where do you actually find these rules?
At the Casino de Monte-Carlo, French roulette is offered exclusively at the grand French table, with a minimum of five euros and a maximum of two thousand euros per bet.
The SBM website confirms this is the only venue within the SBM group offering genuine French roulette.
At that table, if zero lands, the player may choose between La Partage and En Prison, both being offered as options.
The English roulette tables at Monte Carlo, also available at the Casino Cafe de Paris, automatically default to En Prison on all even-money bets.
French-style rules on the French Riviera are the historical norm at licensed French casinos, though the national gambling authority does not mandate them.
They are a traditional commercial practice.
In London, the situation is considerably less generous.
The UKGC does not mandate La Partage.
It is entirely a commercial choice, and most UK floors, even those running single-zero European wheels, do not offer it.
Aspers at Westfield Stratford is one of the few confirmed exceptions: their European tables apply La Partage publicly, reducing the even-money edge to one point three five percent.
This is verified.
For a serious player who cares about edge and doesn't require a Mayfair postcode, that matters.
Online, the rules are more consistently available, precisely because they're commercially straightforward to implement.
Evolution's French Roulette Gold and the Pragmatic Live French Roulette table, which was added to the live dealer catalogue in mid-2025, both apply La Partage on even-money bets as standard.
Playtech's French Roulette table does the same.
On these tables, the rule is automatic: zero lands, half your even-money stake returns, no theatre required.
En Prison is essentially unavailable at online live dealer tables because it's operationally impractical when multiple players at the same table have bets at different stages of imprisonment.
La Partage is the universal online standard because it's a one-step settlement.
The reason La Partage isn't universally offered at UK land-based casinos comes down to margin.
It halves the casino's theoretical revenue on even-money bets.
No regulation requires them to offer it, and most operators don't volunteer to halve their take.
If you want it, you need to find a French table specifically, and most mid-tier UK venues don't have one.
One practical note for anyone planning a trip.
If you are playing even-money bets at a significant stake, the difference between a standard European table and a La Partage table is genuinely meaningful over time.
At one hundred pounds per bet, fifty bets per hour, a hundred hours of play across a year, the difference in expected loss is six thousand seven hundred and fifty pounds.
That is not trivial.
It is worth asking.
La Partage and En Prison are not a strategy.
They don't make roulette a winning game.
They make it a better negative-expectation game, on even-money bets only.
That is all.
But on those bets, it's the best available edge the house will give you at a live table.
