Two companies in the same premises: what the law requires

Updated March 2026 - With rising commercial real estate costs in major French cities, an increasing number of entrepreneurs are considering sharing workspace. The question comes up regularly: can two companies operate from the same premises? The answer is yes, but the legal framework is precise and the risks of non-compliance are real if the arrangement is poorly structured. This guide covers the legal solutions, mandatory procedures and pitfalls to avoid in 2026.

See also postal proxies and correspondence management, characterising a business correctly and tax and social compliance questions.

Under French law, no provision prohibits multiple companies from sharing the same address. Article L123-10 of the French Commercial Code governs company domiciliation and explicitly allows multiple companies to share the same address, provided a formalised framework is in place. What the law monitors is transparency: each entity must remain clearly identifiable, with its own SIREN number, its own accounts and its own distinct legal identity.

The founding principle is straightforward: two companies in the same premises is legal as long as each maintains its own legal and accounting autonomy. The INPI, through the single window for business formalities (guichet unique), readily accepts the registration of multiple SIRET numbers at the same address. This is common practice — commercial domiciliation centres regularly host hundreds of companies under a single roof.

Before choosing a solution, it is essential to distinguish four different legal configurations, each with its own obligations.

Commercial domiciliation. This is the simplest and most widespread arrangement. An approved domiciliation company provides a business address, without the registered companies necessarily conducting their daily operations there. Costs range from €15 to €80 per month depending on the services included (mail handling, telephone answering, meeting room access). Multiple companies can be domiciled at the same address without ever physically crossing paths.

Genuine shared occupation. Two companies physically share the same premises — offices, workspaces, meeting rooms. This situation requires a written premises-sharing agreement defining the allocation of space, costs and access hours. This is the typical case of two freelances jointly renting an office, or an accounting firm sharing its premises with a lawyer.

Commercial subletting. A company holding a commercial lease sublets part of its space to another company. This operation is strictly governed by Article L145-31 of the Commercial Code: the subtenant cannot carry out an activity different from that specified in the head lease, and the subletting rent cannot exceed a rent proportional to the sublet area. The landlord's written consent is mandatory.

Cost-sharing with re-invoicing. One company bears the full lease and re-invoices a share to another user company. This re-invoicing mechanism must be documented by a written agreement, with invoicing that complies with applicable VAT rules. Re-invoicing occupancy costs (rent, electricity, internet) is a VAT-taxable operation and must be correctly accounted for in each entity's books.

Landlord or lessor authorisation

If the premises are rented, the landlord's written authorisation is mandatory before installing a second company. Standard commercial leases generally contain a clause prohibiting subletting or sharing without the owner's express consent. Neglecting this step exposes the tenant to lease termination for breach of contract. If you are the owner, check the building's co-ownership rules: some buildings prohibit multiple professional activities or limit the number of entities that can be installed.

Legal and accounting separation

Each company must have its own SIRET number, its own bank accounts, its own accounting records and its own client contracts. Any mixing between the two structures can be interpreted as a confusion of activities. The tax administration and URSSAF are particularly vigilant on this point. In the event of an audit, the absence of clear separation can lead to reclassification as a de facto partnership (societe de fait), with heavy tax and social consequences: VAT regularisation, social contribution recovery and potential penalties.

Activity compatibility

The two companies must not carry out incompatible or directly competing activities. An architect and a graphic designer can share premises without issue. Two accounting firms, however, risk creating confusion among clients and administrations. Additionally, certain regulated activities (healthcare professions, food activities, hazardous material storage) impose specific hygiene and safety standards that may be incompatible with premises sharing.

Safety and accessibility standards

Depending on the nature of the activities and the number of occupants, certain regulations regarding fire safety, accessibility for disabled persons or reception capacity may apply. It is prudent to verify in advance that the premises comply with requirements for all activities to be carried out there.

Step 1: Check compatibility with the lease and co-ownership rules

Review the current lease carefully. Identify clauses relating to subletting, premises sharing and use of the space. If necessary, request an addendum from the landlord formally authorising the presence of a second company.

Step 2: Draft a sharing or availability agreement

This document must specify the duration of the sharing arrangement, the allocation of costs (rent, electricity, internet, maintenance), each party's access rights, reserved and shared spaces, and the termination conditions. It is strongly recommended to have this agreement reviewed by a lawyer or chartered accountant. The cost of a professionally drafted agreement typically ranges from €200 to €500.

Step 3: Declare the address via the INPI single window

If one of the two companies is changing its address to move into the shared premises, it must update its registration through the single window for business formalities at procedures.inpi.fr. This procedure replaced the former formalities with the commercial court registry (greffe) following the implementation of the single window in 2023.

Step 4: Update the articles of association if necessary

For companies (SARL, SAS, etc.), any change of registered office address requires an amendment to the articles of association, publication in a legal announcements journal and filing with the registry. Associated costs range from €150 to €300 depending on the case.

Step 5: Notify social and tax bodies

Each company must inform URSSAF, the tax authorities (SIE), its pension fund and its professional mutual insurance company of the address change or confirmation. This step is often overlooked but is crucial to avoid lost mail and unnecessary reminders.

The benefits are real: a 30% to 50% reduction in real estate costs, shared equipment (printer, meeting room, internet connection), professional emulation and networking opportunities. For a young business or a freelance in the launch phase, the savings are significant.

The constraints deserve advance planning: confidentiality of exchanges and sensitive documents, increased administrative complexity (two sets of accounts, two declarations, two insurance policies), and the risk of usage conflicts if cohabitation rules are not clear from the outset. A cohabitation charter, even informal, prevents the majority of tensions.

Two micro-entrepreneurs can absolutely share the same business address, provided the activities are distinct and there is no confusion in management. Each declares their revenue independently and retains their own SIRET number.

However, if the two activities are identical or very similar, the risk of reclassification as a de facto partnership by URSSAF is high. This is particularly the case of spouses operating two complementary micro-enterprises from the same premises with shared clients and pooled resources. In this situation, the spouse-collaborator status (conjoint-collaborateur) or the creation of a joint company (SARL, SAS) are legally safer alternatives.

Hayot Expertise advice: the real risk almost always appears when premises sharing has been organised informally — by habit, verbal agreement or assumption. In the event of a tax or social audit, the absence of a written agreement is treated as an absence of rights. A single formalised document protects both companies.

We recommend systematically verifying four elements before committing to a premises-sharing arrangement:

1. ▸The title of occupation: does each company have a written document justifying its right to use the premises (lease, availability agreement or domiciliation contract)?
2. ▸The lease clauses: does the lease permit sharing, subletting or the presence of third parties on the premises?
3. ▸The cost-sharing modalities: is the allocation of charges documented, invoiceable and compliant with applicable VAT rules?
4. ▸The consistency of legal formalities: do the addresses declared to the RCS, URSSAF and tax authorities correspond to the actual occupation of the premises?

Can two SIRET numbers be registered at the same address?

Yes, absolutely. The INPI and INSEE accept the registration of multiple SIRET numbers at the same address without restriction. This is common practice, particularly in commercial domiciliation centres hosting hundreds of companies. No special authorisation is required — each company simply needs a regular title of occupation (lease, availability agreement or domiciliation contract).

What is the risk of a de facto partnership when sharing premises?

The risk of reclassification as a de facto partnership (societe de fait) arises when the administration (URSSAF, tax authorities) finds that two companies share not only premises but also human, financial or commercial resources without reciprocal invoicing. If both structures have shared clients, commingled bank accounts or joint management, they may be reclassified. The consequences are severe: unlimited liability of partners, tax and social regularisation, and penalties. The remedy is straightforward: strict accounting separation, invoicing of services rendered and a written sharing agreement.

Is a contract needed even if both companies belong to the same director?

Yes, always. Even if you personally manage both structures, a written contract protects each entity in the event of a tax audit or dispute with a third party. The tax administration does not recognise informal arrangements between related entities. Each company must be able to independently justify its right to occupy the premises.

How much does it cost to set up a premises-sharing arrangement?

Costs vary depending on the chosen solution. For commercial domiciliation, budget between €15 and €80 per month. For direct premises sharing, the main costs are drafting the agreement (€200 to €500 with a professional), statute modification fees if the address changes (€150 to €300), and legal announcements publication (approximately €150). Sharing occupancy costs typically yields a 30% to 50% saving on the real estate budget.

Can a company be domiciled at a personal residence?

Yes, a company director can register the company's registered office at their personal home, subject to the landlord's consent if the property is rented and the co-ownership rules where applicable. This domiciliation is possible for a maximum period of five years, renewable. However, if the activity involves receiving clients, storing goods or a craft activity, domiciliation at the home may be refused.

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In 2026, two companies operating from the same premises is often perfectly workable — but not without proper verification. Legal security comes from the lease, the documented occupation arrangement and the evidence of separation between the two structures. Whether you opt for commercial domiciliation, a sharing agreement or a sublease, the written document remains your best protection. A tax or social audit is prepared for in advance, not on the day of notification.

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