- If you're PACS'd or married in France, your household counts as a single taxpayer — capital gains from shares, property or crypto are pooled together and declared as one figure, regardless of whose account the sale came from
- The one exception is a mixed household where only one partner holds an S1: you have to split out that partner's exact euro share so the reduced social charges rate applies only to their portion
- Securities, property and crypto gains are three separate silos — you cannot offset a loss in one against a gain in another, and crypto losses cannot be carried forward at all
- Cohabiting couples who are neither PACS'd nor married are taxed completely differently — each partner is their own household, and nothing is pooled
Most people assume their capital gains follow the same rule as their salary — that whoever sold the asset is whoever pays the tax on it. That's not how it works once you're PACS'd or married in France. Your household is treated as a single taxpayer, which means every gain gets added together and declared as one number, no matter which of you actually clicked "sell."
That's usually good news — it simplifies the paperwork. But it creates one specific trap, and it's the one that catches nearly everyone: if only one of you holds an S1 certificate, pooling the gain also pools the social charges rate, unless you actively split it back out again.
Your Household Is One Taxpayer, Not Two
France taxes PACS'd and married couples through the foyer fiscal — the household, not the individual.
Sell some shares from an account in your name only, and the gain still isn't "yours" for tax purposes. It goes into the household's combined total, on the household's return, taxed at the household's rate.
Securities gains work like this: every sale across every account, in either partner's name, gets totalled into one net figure. That figure goes into Box 3VG on Form 2042 C. If your combined result for the year is a loss rather than a gain, it goes into Box 3VH instead, and can be carried forward against future gains for up to 10 years.
Property gains work the same way, with an extra step. A UK property sale needs its own declaration — Form 2048-IMM, technically due within a month of completion — and the net gain then lands in Box 3VZ on your year-end return. This box exists mainly so the gain is correctly reflected in your RFR (revenu fiscal de référence), even if the tax itself was already settled at the time of sale. If the property was your principal residence, the gain is generally exempt — you don't need to report it at all.
Crypto gains are pooled too. Every crypto sale or exchange by either partner, on any exchange, feeds into one household total on Form 2086, which then transfers to Box 3AN or Box 3BN. This form is mandatory even if your total gain is under the €305 exemption threshold and no tax is actually due.
The S1 Trap — Where Most People Lose Money
This is where it gets important. Pooling the gain is simple. Pooling the social charges rate on that gain is where households with mixed S1 status lose money without realising it.
If you hold an S1 and your partner doesn't — or the other way round — your social charges rate isn't the same for both of you. The S1 holder should be paying a reduced rate on their share of the gain. But because the gain itself is declared as one pooled figure, the tax system has no way of knowing which part of it belongs to the S1 holder unless you tell it.
For securities gains, that means entering the S1 holder's individual share of the total gain — usually 50% for a couple with no other agreement — into Box 8RM, in addition to the pooled figure in 3VG. You also need to tick Box 8SH or 8SI to confirm S1 status. Miss 8RM, and the S1 holder ends up paying full social charges on a gain they were entitled to have reduced.
For property gains, there's no dedicated box for the split — instead, you use the "Autres informations" (other information) free-text box on your return to state the non-S1 holder's name and their exact euro share of the figure in 3VZ. It's easy to skip because it doesn't look like a required field. It is, in practice, required if you want the correct rate applied.
See our guides to the S1 explained and social charges in France for full detail on how S1 status affects your social charges rate.
The Three Types of Gain Don't Talk to Each Other
Securities, property and crypto gains are entirely separate categories, even though they all sit under the same "Plus-values et gains divers" heading (Heading 3) on the 2042 C.
The fundamental rule is that losses are only deductible from gains of the same nature.
No cross-offsetting: A loss on shares cannot be used to reduce a gain on a property sale, and property deficits cannot reduce a crypto gain.
Crypto is the strictest category: Digital asset losses are explicitly non-imputable against capital gains from any other type of asset.
How carry-forward works:
| Category | Box for Loss | Carry Forward? | Offset other categories? |
|---|---|---|---|
| Securities (Shares) | 3VH | Yes — 10 years | No |
| Property | Varies by regime | Varies | No |
| Digital Assets (Crypto) | 3BN | No | No |
Crypto losses are use-it-or-lose-it. If you don't have a crypto gain in the same tax year to offset it against, the tax benefit of that loss is gone.
What If You're Cohabiting but Not PACS'd or Married?
This is a genuinely different tax situation, and it's easy to confuse with PACS. Couples living together in France without formalising their relationship — known as union libre or concubinage — are treated as two entirely separate tax entities. None of the pooling rules above apply.
Each partner is their own foyer fiscal. Capital gains from securities, property or crypto are declared on each partner's individual return, at each partner's individual rate.
The S1 mixed-household rule does not apply — because there's no combined household to split in the first place. If one cohabiting partner holds an S1, they simply tick Box 8SH on their own return. It has no bearing on the other partner.
Even if the couple have children together, they remain taxable separately for income tax purposes, with each partner claiming the tax parts for the children they personally support.
Common Mistakes
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Assuming the gain "belongs" to whoever sold the asset. For PACS'd and married couples, it doesn't — it belongs to the household, full stop.
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Forgetting Box 8RM (or the property note jointe) in a mixed-S1 household. This is the single most common way an S1 holder ends up overpaying social charges without ever knowing it happened.
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Trying to offset a loss in one asset category against a gain in another. Securities, property and crypto are three separate silos on your return — they never cross over.
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Forgetting that crypto losses don't carry forward. Unlike securities losses, a crypto loss not used in the same tax year is simply lost.
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Applying household pooling rules to a cohabiting-but-not-PACS'd relationship. If you haven't formalised the relationship, you're each your own household — nothing pools.
Frequently Asked Questions
I'm PACS'd and realised capital gains in 2025 — will they be taxed on me alone or on both of us?
They'll be taxed on your household as a whole, not on you individually. Your gain is combined with any capital gains your partner made in the same category — for example, all securities gains together — and declared as one pooled figure on your joint return.
I have capital losses that outweigh my spouse's capital gains — how do I offset them across different boxes?
If they're the same type of asset (both securities, for example), you don't need to do anything separately — the household total in Box 3VG or 3VH already nets your gains and losses together automatically. You cannot offset a loss in one category against a gain in a different category, like property or crypto.
We're cohabiting but not PACS'd — are we taxed the same way?
No. If you haven't formalised your relationship through PACS or marriage, you're each treated as your own household for tax purposes. Your capital gains are declared separately, with no pooling and no S1 apportionment box to think about.
Only one of us has an S1 — do we still need to split out the gain if it's small?
Yes. There's no minimum threshold below which the S1 apportionment stops mattering — if the gain is pooled and only one partner holds an S1, that partner is entitled to the reduced social charges rate on their share, and the box needs completing to claim it.
Can crypto losses be carried forward to next year like securities losses can?
No. Crypto losses can only be offset against crypto gains made in the same tax year. If you don't have a crypto gain to offset it against, the loss cannot be carried forward and cannot reduce gains from other asset types.
What happens if I sold UK property and missed the one-month filing deadline?
You may face late payment interest, but you still need to complete Box 3VZ on your year-end return regardless — this ensures the gain is correctly reflected in your household's RFR even after the fact. Contact your local tax office if you're catching up on a missed deadline.