Since 1 January 2023, all French company formalities (formation, amendment, cessation, accounts filing, trademark filing, patent filing) must go through the INPI Guichet Unique: procedures.inpi.fr. At the end of each formality, the portal generates a PDF summary that you must sign electronically before validation.
This signature is the last step but also the most problematic: misunderstood required level, FranceConnect+ failures, signatures of the wrong level rejected. This guide tours the topic completely.
What signature level does the Guichet Unique require?
The Guichet Unique requires the highest level of EU eIDAS regulation: the qualified electronic signature (Qualified Electronic Signature, QES). This level has 4 cumulative characteristics:
- The signer is reliably identified (PVID verification).
- The signer is solely in control of the signing means.
- The integrity of the document is cryptographically guaranteed (any post-signing modification is detected).
- The certificate is issued by a Qualified Trust Service Provider listed on the EU Trust List.
Point 4 excludes most market solutions: Adobe Reader, basic Yousign Pro, DocuSign Standard, signature scanners. See advanced vs qualified signature.
Which INPI formalities require a qualified signature?
Almost all formalities going through the Guichet Unique require a qualified signature:
| Formality | Qualified signature required? |
|---|---|
| Articles amendment | ✅ MANDATORY |
| Business cessation / RCS deregistration | ✅ MANDATORY |
| Annual accounts filing | ✅ MANDATORY |
| INPI trademark filing | ✅ MANDATORY |
| Patent filing | ✅ MANDATORY |
| Company formation (standard) | ⚠ Depends (FranceConnect+ produces qualified in standard flow) |
| Formation with in-kind contributions or complex bylaws | ✅ MANDATORY (externalised qualified signature) |
Routes to a qualified signature
Route 1: FranceConnect+ via certified La Poste Digital Identity
The "official" route offered by the Guichet Unique. The State funds the national digital identity infrastructure, which makes this route free for the user.
Conditions:
- Have a La Poste Digital Identity account at certified level (physical verification at a post office).
- Time to obtain: 2 to 5 working days.
- FranceConnect+ must work when you sign (frequent failures, see FranceConnect+ doesn't work on INPI).
Route 2: Pay-as-you-go qualified provider
You download your PDF summary, drop it on a service like SignerSynthèse.fr, the provider applies the qualified signature, and you receive the signed PDF by email. Time: 2 to 5 minutes. Cost: €29 ex. VAT at SignerSynthèse.fr.
Particularly suited for urgent formalities or in case of FranceConnect+ failure.
Route 3: Qualified certificate on USB token or smart card
French recognised issuers: Certigna, Certinomis, Certeurope. Time: 1 to 4 weeks. Cost: €100 to €250 ex. VAT for 1 to 3 years. Suited for accountants and lawyers signing dozens of formalities per year.
Route 4: Qualified SaaS platforms
Yousign Pro+, DocuSign Business Pro with qualified signature activated. Cost: €300 to €800 ex. VAT/year minimum. See pricing comparison.
No time for FranceConnect+? €29 ex. VAT, 2 minutes.
eIDAS qualified electronic signature via Universign (EU Trust List), 100% accepted by the INPI Guichet Unique.
Sign my summary →How does the Guichet Unique verify the signature?
The INPI Guichet Unique uses an automatic cryptographic verification engine that analyses the signed PDF without human intervention. Steps:
- Reading signature metadata: eIDAS fields, certificate identifier, timestamp.
- Certificate chain verification: is the issuer certificate on the EU Trust List?
- Qualification OID verification: does the certificate carry the QC (Qualified Certificate) or QSCD (Qualified Signature Creation Device) marker?
- PDF integrity verification: has the document hash been modified after signing?
- Revocation check: is the certificate still valid (not revoked, not expired)?
If all checks pass, the formality is validated instantly. If even one fails, rejection with a generic message.
Most frequent errors
Error 1: Signing with Adobe Reader
Adobe's simple signature is rejected. See INPI summary rejected.
Error 2: Modifying the PDF before signing
Opening the PDF summary in Adobe Reader and saving (even without visible modification) alters metadata. The Guichet Unique compares the hash of the re-uploaded PDF with the one it generated: if different, rejection.
Error 3: Believing standard FranceConnect+ is enough
A La Poste Digital Identity at "verified" level (without physical certification) is not enough for qualified. You need the "certified" level.
Error 4: Confusing advanced and qualified signatures
Basic Yousign Pro, DocuSign Standard produce advanced signatures, not qualified. See Advanced signature rejected by INPI.
Legal deadlines to know
- Articles amendment: signature to be filed within one month of the AGM.
- Annual accounts filing: 7 months after fiscal year close (or 8 months if AGM delayed).
- Business cessation: 1 month after the decision.
- Trademark filing: no legal deadline, but monthly cost of delay if you wait.
Conclusion
The INPI Guichet Unique is the only entry point for your French company formalities since 2023. The eIDAS qualified signature is the last step — and the most tricky. Prepare it well: check your La Poste Digital Identity level if you want the free route, or choose a pay-as-you-go qualified provider if you're in a hurry.
For 99% of directors signing 1 to 3 formalities per year, pay-as-you-go service (€29 ex. VAT, 2 minutes, 100% accepted) remains unbeatable against FranceConnect+ constraints.