Renting out your cellar as storage space can earn you a few dozen euros per month in most French cities. However, renting your cellar as a living space faces a strict legal framework that makes the operation nearly impossible in a typical cellar.
The difference between these two scenarios lies in a few measurable criteria: area, ceiling height, ventilation, natural light, and energy classification. This article compares the two options and details the parameters that determine what an owner or tenant can actually do with this underground space.
Storage cellar vs. living cellar: comparison of regulatory constraints
The distinction between storage use and residential use is based on specific technical criteria. The table below summarizes the differences between the two configurations.
| Criterion | Rental as storage | Rental as housing |
|---|---|---|
| Applicable contract | Common law contract (Civil Code) | Residential lease (law of July 6, 1989) |
| Window or opening to the outside | Not required | Mandatory (sufficient natural light) |
| Ceiling height | No legal minimum | Minimum required by decency standards |
| Ventilation | Recommended, not imposed | Ventilation compliant with health standards |
| Energy performance diagnosis (DPE) | Not required | Mandatory, F/G classification potentially blocking |
| Declaration to the town hall | Not necessary (accessory use) | Mandatory change of use |
| Insurance | Civil liability is sufficient | Full home insurance required |
Most underground cellars do not meet any of the criteria required for housing. The absence of a window alone is enough to render the space unsuitable for living according to French regulations.
For owners looking to explore all options before proceeding, the process of renting out their cellar as housing requires checking each technical point in advance.
DPE and Climate Law: why the cellar is trapped by energy classification
Common content on cellar rentals rarely mentions the energy performance diagnosis. This is a significant omission. Since the Climate and Resilience Law of August 22, 2021, homes classified as G are gradually banned from being rented, followed by those classified as F.
A cellar converted into a living space accumulates thermal disadvantages: massive thermal bridges, lack of natural ventilation, insulation often non-existent. The predictable result is an F or G classification on the DPE.
The direct consequence is clear: even a renovated cellar may be prohibited from residential rental in the short or medium term. The timeline for banning energy sieves is currently under discussion for potential adjustments, but the trend remains towards tightening regulations for atypical small housing.
For an owner considering renovation work, the cost of bringing an underground space up to energy standards far exceeds that of a typical home. Interior insulation reduces the already limited living space, and installing an efficient mechanical ventilation system in a space without openings poses significant technical constraints.
Co-ownership and change of use: obstacles even before the work
Transforming a cellar into a living space in a collective building requires two distinct authorizations that block most projects.
- The general assembly of co-owners must vote on the change of use of the lot. This vote usually requires a qualified majority, and co-owners often oppose it for reasons of safety, nuisance, and property value.
- The town hall must grant a building permit or a prior declaration for the change of use. In dense urban areas, such requests are subject to careful examination, particularly regarding accessibility and fire safety standards.
- The co-ownership regulations may explicitly prohibit any residential use of cellars, making the project impossible without modifying these regulations (another vote in the general assembly).
The absence of co-ownership agreement is enough to block the project, regardless of the condition of the cellar or the owner’s intentions. Disputes on this subject are increasing, with some co-ownership syndicates taking action to reclassify illegally rented cellars as living spaces.
Actual profitability: rental storage vs. conversion to housing
The question of profitability deserves to be asked directly. The income from a cellar rented for storage varies depending on location and size, but the investment/return ratio clearly favors storage.
Renting as storage space requires no work to meet standards, no DPE, no change of use. The owner freely sets the rent and contractual conditions (a common law contract is sufficient). Rental income from a cellar is taxed in the category of property income.
In contrast, converting a cellar into a living space requires significant work:
- Creation of openings (if technically possible), complete thermal insulation, efficient mechanical ventilation
- Electrical compliance, connection to networks, fire safety standards
- Administrative costs: building permits, mandatory diagnostics, potential modification of co-ownership regulations
The return on investment for a conversion to housing generally takes many years, with no guarantee that the energy classification obtained will remain compatible with future regulatory requirements.
Lease and insurance for a cellar rented as storage
When a cellar is rented alone (without an associated living space), it does not fall under the law of July 6, 1989. The owner and tenant sign a common law contract governed by the Civil Code. The duration, rent, and termination conditions are freely negotiated between the parties.
If the cellar is rented as an annex to a living space, it is included in the main residential lease. It then follows the same rules as the housing: lease duration, rent control if applicable, termination conditions.
Regarding insurance, the tenant of a storage space must at least have civil liability covering damages caused to the premises. The landlord, on the other hand, should ensure that their non-occupant owner insurance explicitly covers the rental of the cellar, as some contracts exclude separately rented dependencies.
Renting a cellar for storage remains an accessible source of additional income, provided that the line of residential use is not crossed. The DPE, co-ownership, and decency standards form three locks that make conversion to housing costly, uncertain, and legally risky. Focusing on rental storage, with a clear contract and appropriate insurance, remains the safest way to enhance this space.