For international buyers and non-residents, the French property market is a top-tier destination for both lifestyle and investment. One of the most common questions we receive is whether it is possible to co-borrow with a family member—such as a spouse, adult child, or sibling—to facilitate the purchase.

The answer is yes, but with a significant caveat: French banks do not lower their guard for joint applications. Whether your co-borrower is a resident in France or based overseas, the lending criteria remain among the most rigorous in the world.

The “Solo-Stress Test”: Understanding DSTI

The cornerstone of French lending is the Debt-to-Income (DSTI) ratio, which is legally capped at 35%. While many international markets allow for flexibility based on high net worth or future rental projections, French banks prioritize immediate, proven affordability.

When applying with a family member, you must satisfy the 100% Rule:

• Individual Affordability: At least one borrower must independently meet the 35% DSTI threshold while being able to cover 100% of the monthly loan instalment on their own.

• The Logic: French regulators want to ensure that if one co-borrower loses their income or if the relationship dynamic changes, the loan remains sustainable for the primary applicant.

• Global Debt Calculation: This 35% limit is inclusive of all global debts, including mortgages on properties in the US, UK, or UAE, personal loans, and the projected French mortgage payment.

Eligibility and Requirements for Co-Borrowers

Adding a family member to the deed and the mortgage means they are scrutinized with the same intensity as the lead applicant. There are no “silent partners” in French mortgage contracts.

1. Full Documentation: Every borrower must provide three years of tax returns, audited accounts (if self-employed), bank statements, and proof of assets.

2. Solidarity Clause: All French mortgages involve a “solidarity” clause. This means the bank can legally demand the full repayment of the debt from any of the co-borrowers, regardless of their original share of the contribution.

3. Age and Term Constraints: The loan term is usually dictated by the oldest borrower. If you are co-borrowing with a parent to help with their retirement home, the loan term may be shorter (typically ending by age 75), which can significantly increase the monthly payments.

4. Mandatory Insurance: Both parties must be insured. Banks often require 100% coverage for each borrower. While this adds to the cost, it ensures that if one borrower passes away, the loan is fully repaid by the insurance, protecting the surviving family member and the bank.

Why Co-Borrowing Remains a Strategic Move

Despite the strict math, involving a family member offers several elite financial advantages:

• Succession and Inheritance: By including children in the mortgage and ownership structure (often via an SCI), you can simplify the eventual transfer of the estate and mitigate future inheritance tax burdens.

• Wealth Tax Optimization: For properties valued over €1.3 million, the debt associated with the mortgage can be used to reduce the net taxable wealth, potentially staying below the IFI (Impôt sur la Fortune Immobilière) threshold.

• Resident/Non-Resident Synergy: If one family member is a French resident with a stable CDI (permanent contract), it can provide a “bridge of trust” for the bank, even if the non-resident borrower provides the majority of the capital.

Conclusion: The Importance of Specialist Advice

Securing a French mortgage as a non-resident is a marathon of compliance and financial engineering. Because at least one borrower must meet the 100% affordability threshold, the way you present your global income, assets, and family structure to the bank is the difference between an approval and a rejection.

Given these complexities—and the fact that not all banks are willing to work with international profiles or specific family structures—it is essential to consult with a specialist.

BlueSky Finance acts as your advocate in the French market. We understand the “Solo-Stress Test” and know exactly which lenders are currently active in the non-resident space. We don’t just find you a rate; we architect a solution that respects French regulations while meeting your family’s global investment goals.