- A tontine clause (clause de tontine or clause d'accroissement) makes the surviving buyer treated as if they'd owned the whole property from day one — it bypasses the deceased's heirs entirely
- It can only be added at the time of purchase — you cannot convert an existing property into a tontine later
- For unmarried couples, the tax bill on the survivor's share can still reach 60%, with a narrow exception for a main residence worth under €76,000
- For married or PACS couples it's largely unnecessary for tax purposes — they already inherit from each other tax-free
If you're buying property with a partner you're not married or PACSed to, French succession law doesn't protect them the way a UK will might assume. A tontine clause is the standard notarial tool for closing that gap — but it comes with real trade-offs that are worth understanding before you sign.
What a tontine clause actually does
Normally, when co-owners buy property together (en indivision), each person's share becomes part of their own estate when they die. That share passes to their heirs — not automatically to the co-owner — unless a will or other planning says otherwise.
A tontine clause changes this at the root. Written into the purchase deed itself, it states that whichever buyer survives is treated, retroactively, as having owned the entire property alone from the date of purchase. Legally, the deceased's share never passed through their estate at all — there's nothing for their heirs to inherit, because in the eyes of the law they never had a permanent share to leave.
This is what makes a tontine effective against forced heirship. Because the property is deemed to have always belonged solely to the survivor, a deceased partner's children from a previous relationship — who would otherwise have a protected claim under the réserve héréditaire — have nothing to claim against. For more on how forced heirship normally works, see our guide to how inheritance tax works in France.
It only works if set up at purchase
This is the clause's biggest practical limitation: it has to be written into the deed when the property is bought. There is no way to add a tontine clause to a property you already jointly own — you would need to sell and repurchase, which brings its own costs and complications.
If you're buying property with a partner and want this protection, it needs to be raised with the notaire before signing, not after.
The tax bill for unmarried partners is still steep
A tontine solves the ownership problem — who legally ends up with the property — but it does not solve the tax problem on its own. French tax law treats what the survivor receives under a tontine clause as a gratuitous transfer (Article 754 A of the CGI), taxed according to the relationship between the two people, exactly like an ordinary inheritance.
For an unmarried couple with no other relationship recognised by French tax law, that means the survivor's share falls into the "unrelated person" band: a €1,594 allowance, then 60% tax on the rest.
There is one narrow exception. If the property is the couple's shared main residence and its value is under €76,000 at the date of death, the transfer is exempt from the standard succession-style tax and the survivor pays ordinary property transfer tax (roughly 5%) instead — though the survivor can choose to be taxed under the normal succession rules if that works out better for them. This threshold hasn't been revalued since 1980 and is well below most French property values today, so in practice it rarely applies outside older, lower-value homes in less expensive areas.
All of the above — the €1,594 allowance, the 60% rate, the €76,000 exception — only applies if the two buyers are unmarried. Married or PACSed partners are unaffected by any of it, because they inherit from each other completely tax-free by default, tontine or no tontine. For a married or PACSed couple, a tontine can still be useful for civil-law reasons (it can simplify or speed up how the survivor takes full ownership, avoiding probate-style delays), but it isn't fixing a tax problem, since there was never one to fix.
The likely catch on the second death
A tontine only protects the first transfer — from the deceased partner to the survivor. When the survivor later dies, the property passes to their heirs under the normal succession rules, calculated fresh at that point.
The trade-off commonly flagged in estate planning is this: because the first partner's share is deemed, retroactively, to have never been part of their estate, their personal tax-free allowance is never used against the property at all. Compare that to a couple who owned the property jointly without a tontine, each leaving their half through a will and each using their own allowance — in that scenario, two allowances get used across the two transfers instead of effectively one. This is the standard argument against using a tontine purely as a tax-minimisation tool, though the exact numerical impact depends on the specific estate and is worth modelling with a notaire rather than assumed.
Either way, it's a genuine trade-off, not just a technicality: a tontine protects the survivor very effectively and certainly, at a cost that shows up later, on the second death.
Watch for requalification as a disguised gift
French tax authorities can challenge a tontine clause and reclassify it as a disguised donation (donation déguisée) if it doesn't look like a genuine bet on an uncertain outcome. Two things commonly trigger scrutiny:
- Unequal contributions to the purchase price, without a clear justification (a meaningfully younger buyer covering a larger share, reflecting their longer life expectancy, is generally accepted — a large unexplained imbalance is not)
- A significant age gap between the buyers — roughly a 20-year difference is often cited as a red flag that tax authorities and courts look at closely
If a tontine is reclassified as a disguised gift, the tax advantages disappear and the transfer is taxed as an ordinary gift instead — potentially at a worse rate than if no tontine had been used at all. This is a genuine risk for arrangements like grandparents buying property jointly with a much younger grandchild, where the "risk" the tontine is supposed to hinge on isn't realistic.
Tontine vs SCI vs simple joint ownership
For unmarried couples specifically, a tontine is one of three common approaches to holding property together, alongside an SCI (Société Civile Immobilière) or simple co-ownership with wills. A tontine gives the strongest, most automatic protection to the survivor but is rigid, irrevocable, and tax-heavy if the relationship isn't married or PACSed. An SCI offers more flexibility — shares can be structured, transferred gradually, or split between usufruct and bare ownership — at the cost of more setup and ongoing administration. See our full guide to using an SCI to pass on French property.
Common mistakes
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Assuming a tontine avoids inheritance tax for unmarried partners. It changes who ends up owning the property, not how that transfer is taxed. The 60% band still applies above the small allowance and the narrow €76,000 main-residence exception.
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Trying to add a tontine clause after the property is already owned. It can only be set up at the point of purchase — there's no way to retrofit it onto an existing joint ownership arrangement.
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Not accounting for the second death. A tontine protects the first transfer well but, on the standard estate-planning argument, uses up one partner's allowance without benefit — worth modelling with a notaire rather than assuming either way for a specific estate.
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Contributing unequally to the purchase without documenting why. An unexplained imbalance in who paid what, especially combined with a large age gap between buyers, is exactly what invites a disguised-gift challenge.
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Assuming it's necessary for married or PACS couples. They already inherit from each other tax-free without a tontine — it may still have civil-law uses for them, but it isn't solving a tax problem.
Frequently Asked Questions
Can I add a tontine clause to a property I already own jointly?
No. A tontine clause must be written into the purchase deed at the time the property is bought. There is no mechanism to add it retroactively to an existing joint ownership arrangement.
Does a tontine avoid French inheritance tax for an unmarried partner?
No. It changes who legally ends up owning the property, but the transfer to the survivor is still taxed as a gift under Article 754 A of the CGI, using the same rates as an ordinary inheritance between unrelated people — up to 60% above a €1,594 allowance, with a narrow exception for a shared main residence worth under €76,000.
Is a tontine clause useful for married or PACS couples?
Not for tax purposes — married and PACS partners already inherit from each other completely tax-free. A tontine can still simplify how ownership passes to the survivor, but it isn't solving a tax problem for couples in that position.
What happens when the surviving partner in a tontine later dies?
The property passes to the survivor's own heirs under the normal succession rules, calculated fresh at that point. Because the first partner's share was structured to bypass succession entirely, their personal allowance was never used against the property — the standard argument in estate planning against relying on a tontine purely to minimise tax, though the exact impact depends on the estate and is worth modelling with a notaire.
Can a tontine clause be challenged by the tax authorities?
Yes. If the arrangement doesn't reflect a genuine shared risk — for example, if the buyers contributed very unequally without justification, or there's a large age gap between them — it can be reclassified as a disguised gift (donation déguisée), losing its tax treatment and potentially triggering ordinary gift tax instead.
For more on this topic, browse our Inheritance & Succession Tax category.