Damp and mould in French rented homes: who is responsible?
Mould on a wall does not alone identify responsibility. Water penetration, faulty ventilation, thermal bridging and occupancy conditions can combine. Establish and address the cause rather than simply repainting.
This guide concerns French main-residence rentals. It distinguishes technical diagnosis, tenancy duties and remedies. A photograph replaces neither technical assessment nor medical advice.
1. Record the problem precisely
Note affected areas, onset, known rainfall or leaks and observed changes. Take overview and detail photographs without unnecessary private information. Humidity readings can support the file but do not alone establish fault.
If water is still entering, follow the useful immediate steps in the leak guide. If health symptoms arise, seek medical advice rather than diagnosing their cause remotely.
2. Examine several possible causes
| Observation | Possibility to investigate, not an automatic conclusion |
|---|---|
| Marks after rainfall | Roof, façade or other penetration |
| Stain near a pipe | Leak or consequences of water damage |
| Condensation and limited air renewal | Ventilation operation and use conditions |
| Recurring mould on cold surfaces | Insulation, thermal bridges and ambient humidity |
| Problems despite routine upkeep | Building and equipment diagnosis |
The Health Ministry describes several possible causes (opens in a new tab). Advice to ventilate does not establish building compliance; a photograph of a dark patch does not establish a single cause either.
3. Separate the duties
Landlords must provide and maintain housing meeting applicable requirements. Official housing standards (opens in a new tab) include protection from relevant water ingress and air renewal appropriate for normal occupation.
Tenants must use the home normally, undertake their routine maintenance and report defects. Established maintenance failures can matter but do not remove the owner's duties concerning faulty ventilation or structural problems.
Our repair responsibility guide distinguishes upkeep, wear and construction defects. Multiple causes need evidence rather than arbitrary equal splitting.
4. Arrange diagnosis and intervention
Send written observations, request examination of causes and agree access. Appropriate professionals can check ventilation, water entry, surfaces and equipment. The occupied-property works guide explains arrangements and notifications.
Keep pre-treatment records where this does not delay necessary action. Surface cleaning can remove a mark while leaving its source active. Do not improvise hazardous treatments or mix products; use guidance appropriate to the extent and situation.
5. Check effectiveness, not just the invoice
After work, record completed measures and observations to monitor. If the problem returns, document dates and areas rather than assuming an invoice proves resolution.
A DPE concerns energy performance, not every cause of damp. The F/G and housing-standards guide separates these issues. Inspection photographs may establish previous condition without answering the present technical question.
6. Handle disagreement or inaction
Keep requests and replies, then seek ADIL or relevant-service advice about housing standards, conciliation and remedies. A court may order measures depending on the case; this is not a general right to reduce or withhold rent unilaterally.
Suspected danger or unhealthy housing warrants assessment of the appropriate route without waiting for the next inspection. Retain reports, diagnoses, appointments and works with the rental documents.
Frequently asked questions
Is drying laundry automatically proof of tenant responsibility?
No. Usage can inform diagnosis, but ventilation, building condition and other moisture sources also need examination.
Is repainting enough to close the matter?
Not if the cause remains. Distinguish removing marks, correcting the source and checking the result.
Can the cost automatically be deducted from the deposit?
No. Deposit deductions require justification and consideration of responsibility, not simply a mark at departure.
Sources checked on 29 October 2026: Health Ministry indoor-air guidance (opens in a new tab), housing standards (opens in a new tab), Articles 6–7 of the 1989 law (opens in a new tab). General information about French law.