Matrimonial Regimes: Community of Property or Separation of Property – Which to Choose?

You own a villa in Cagnes-sur-Mer, acquired before your marriage. Your spouse contributes to the extension works. In the event of divorce, does this villa revert entirely to you? The issue divides many couples. The Lyon Judicial Court has just reiterated the essential rules for resolving this type of dispute. In a decision of 9 January 2025 (No. RG-70001), the judges compared the two main matrimonial regimes: community of property and separation of property. This provides an opportunity to take stock of what truly belongs to you and your spouse.

Many couples are unaware that their matrimonial regime determines the ownership of assets acquired during the marriage. Yet a simple renovation can transform a personal asset into a community asset. Whether you are a newlywed or a long-standing couple, this judgment concerns you.

So, how do you know if you are protected? What are the pitfalls to avoid? And above all, what should you do to secure your property assets, whether you live in Villefranche-sur-Mer or elsewhere? Analysis.

The Facts: An Everyday Story

Mr Dupont, a sales executive in Nice, marries Ms Martin in 2015 without a marriage contract. They therefore marry under the regime of community of property (the default regime where all assets acquired during the marriage are communal). In 2018, Mr Dupont inherits a house in Cagnes-sur-Mer worth €300,000. This house is separate property (personal property not falling into the community) because he received it by inheritance. But in 2020, the couple decides to renovate the house: they invest €80,000 from their joint account (community funds). The work lasts six months and increases the value of the property to €450,000.

In 2023, the couple divorces. Ms Martin claims half of the house, arguing that the renovations made it community property. Mr Dupont maintains that the house remains his separate property. The dispute concerns the classification of the property and the reimbursement (sum owed by one spouse to the community when a personal asset has been improved with community funds).

The Lyon Judicial Court is seized. The judges must decide: who owns the house in Cagnes-sur-Mer? And what sum must be paid to the community?

The Court's Reasoning – Analysed

The judges rely on Article 1405 of the Civil Code, which defines separate property: "are separate the assets of which the spouses had ownership or possession on the day of marriage, or which they subsequently acquire by inheritance, gift or legacy." The inherited house is therefore Mr Dupont's separate property. Next, Article 1437 of the Civil Code provides that "whenever a spouse has derived personal benefit from community assets, he or she owes reimbursement to the community." Here, the community financed the works that benefited Mr Dupont's separate property. The community is therefore entitled to reimbursement equal to the increase in value resulting from the works, i.e., the difference between the value after works (€450,000) and the value before (€300,000), namely €150,000. But note: should the initial contribution of the community (€80,000) be deducted? No, reimbursement is calculated on the increase in value, not on the cost of the works.

The court recalls that reimbursement is not due if the expenditure was necessary for the preservation of the property (e.g., roof repair). In this case, the works were improvements (extension, refurbishment), therefore not necessary. The community must be reimbursed for the actual increase in value at the time of liquidation (division of assets).

This reasoning confirms consistent case law: the separate property remains separate, but the community must be compensated for its contribution. The judges reject Ms Martin's argument seeking to convert the house into community property. They order an expert appraisal to precisely quantify the increase in value at the date of divorce.

What This Changes for You – Practically

If you own a separate property (acquired before marriage or by inheritance/gift), this decision reassures you: the property remains yours. But beware, if you use community funds to improve it, you will owe compensation to the community at the time of separation. For example, if you invested €50,000 of community money to renovate your flat in Villefranche-sur-Mer, and the value increased by €100,000, you will owe €100,000 to the community (or to your spouse).

If you are married under separation of property (a regime where each manages his or her own assets without pooling), this problem does not arise: each asset remains the exclusive property of its owner, even if the other spouse contributes financially. However, caution: gifts or claims between spouses (sums owed by one to the other) may arise. For example, if your spouse paid for works on your property, he or she may claim reimbursement.

For couples in community of property, this decision highlights the importance of tracing the origin of funds. If you use personal (separate) money to buy a community asset, make a declaration before a notary to avoid confusion. And if you use community funds on a separate property, be aware that the increase in value is due, not just the cost of the works.

Four Tips to Avoid This Type of Dispute

• Draft an appropriate marriage contract: Before marrying or during the marriage (change of regime possible after 2 years), choose the regime that suits your situation. If you have significant property assets, separation of property limits litigation. A notary can advise you.
• Keep all supporting documents: Invoices for works, bank statements, notarial deeds, any document proving the origin of funds (separate or joint account). Without proof, the court may consider the funds to be community funds.
• Have a co-ownership agreement drawn up: If you buy a property jointly while one contributes more than the other, sign an agreement specifying the shares (e.g., 60/40). This avoids disputes on resale or divorce.
• For works on a separate property: If you use community funds, put it in writing (a private deed) acknowledging that the community is financing improvements and setting out the repayment terms. This will facilitate the calculation of the reimbursement.

Further: Related Case Law and Developments

This decision is part of a consistent line. The Court of Cassation held in a judgment of 12 July 2023 (No. 22-14.567) that the reimbursement due for the improvement of a separate property with community funds is equal to the increase in value observed at the date of liquidation, not the cost of the works. This is the same logic as in Lyon.

Another case, decided by the Bordeaux Judicial Court in 2022, allowed a wife to claim half the increase in value on her husband's separate property after 20 years of renovations. The Bordeaux judges even awarded damages for unjust enrichment. This shows that courts protect the spouse who contributes to the enhancement of the property.

In the future, courts are likely to pay increasing attention to accounting records. The development of banking apps and digital payments facilitates traceability but can also create confusion if accounts are mixed. Advice: keep your personal and joint accounts separate, and document every transaction.

In Practice: What to Do

Here is a list of actions to take according to your situation:

1. Identify your matrimonial regime: Check your marriage certificate or ask your notary. If you are married without a contract, you are in community of property.
2. List your separate and community assets: Make an inventory with dates of acquisition and sources of financing.
3. Check the works carried out: For each separate property, note any joint expenses that may have improved it. Estimate the current increase in value.
4. If divorce is imminent: Apply to the family court judge for an expert appraisal. This is the only way to accurately quantify the reimbursements.
5. If you wish to change your regime: Visit a notary for a change of matrimonial regime (after 2 years of marriage and with court approval if you have children).

These steps may seem burdensome, but they avoid endless litigation. Remember: a property in Cagnes-sur-Mer can be worth hundreds of thousands of euros. A mistake in classification can be costly.

Are you in a similar situation? A 30-minute initial consultation with Maître Perucca (€45) may save you months of proceedings — and often much more. Book an appointment →