LMNP and SIRET: mandatory or not in 2026?

Updated March 29, 2026 - The short answer is yes: when you start a furnished rental activity, you must declare this start and obtain a SIRET number. In 2026, the DGFiP is very clear on this point.

The impots.gouv.fr sheet updated on January 27, 2026 specifies that the non-professional or professional furniture rental company must declare the creation or start of activity within 15 days following the first day of rental. This formality is done online at the formalities counter, which allows you to obtain a SIRET.

To complete, see LMNP tax, LMNP tax package and CFE LMNP.

The SIRET is used in particular to:

• ▸formalize the activity;
• ▸choose or report the tax regime;
• ▸create a professional space if necessary;
• ▸fulfill certain reporting obligations.

Being "non-professional" in the tax sense does not exempt you from administrative formalities. LMNP does not mean “without registration”.

• ▸start renting without declaring the start of activity;
• ▸believe that SIRET is only useful in LMP;
• ▸wait for the first income tax return to regularize.

Hayot Expertise advice: in LMNP, SIRET is not a comfort option. It is a basic building block of your declaration security.

We help lessors to carry out the correct formalities from the start and to articulate SIRET, tax regime, CFE and declarations.

Quick link: Put your LMNP on its own administrative rails

In 2026, an LMNP is intended to have a SIRET from the start of activity. The real question is not “do we need a SIRET?” but “did I carry out the formality at the right time?”

Contact: Do you want to check if your LMNP is correctly registered and declared? Our firm can take over your situation before the next tax due date. Make an appointment with Hayot Expertise

(Official sources: impots.gouv.fr - start of furnished rental and professional space activity)