You signed your INPI summary, you upload it on the Guichet Unique, and the portal returns a generic message: "Signature non conforme" or "Document non valide". Frustrating, especially after spending 30 minutes (or several days) on the formality. Here are the 7 most common rejection reasons, in descending order of frequency.

Reason 1 — Non-qualified signature (60% of cases)

By far the most frequent. The Guichet Unique requires an eIDAS qualified signature (the highest level). It rejects:

Fix: re-download the original PDF summary, sign it with a qualified provider on the EU Trust List (SignerSynthèse.fr, Universign, etc.). 2 minutes.

Reason 2 — PDF modified after generation (15% of cases)

The INPI Guichet Unique computes a cryptographic hash of the PDF when it generates it. When you upload it back, it compares the hashes. If they differ, rejection — even if the signature itself is valid.

What modifies the hash:

Fix: re-download the original PDF from the Guichet Unique without opening or modifying it, and sign directly via a qualified provider that doesn't alter the file.

Reason 3 — Wrong file uploaded (10% of cases)

You upload the original PDF instead of the signed PDF. Or you upload a draft instead of the final summary.

Fix: verify the filename (signed PDFs usually have a `_signed` suffix or similar), and check that you can see the signature in the PDF (open in Adobe Reader, click signature pencil at top).

Reason 4 — Wrong signer (5% of cases)

The Guichet Unique does not verify that the signer matches the formal signer (it only checks technical signature compliance). But once filed, the formality can be challenged if the signer was not authorised.

For an SAS or SARL: the chairman or director in office signs. For a SCI: the statutory manager. For a partnership: the managing partner.

To remember The qualified signature is strictly personal. Sign yourself, not for someone else. A signature by proxy requires an authentic act with a notary or a specific procedure.

Reason 5 — Expired or revoked certificate (3% of cases)

The qualified certificate used to sign has expired or been revoked between signing and uploading. Rare but happens.

Fix: re-sign with a fresh qualified certificate.

Reason 6 — Provider not on EU Trust List (3% of cases)

You signed with a non-qualified provider that mistakenly advertises itself as "qualified". The Guichet Unique cryptographically checks the EU Trust List and rejects.

Fix: verify your provider on eidas.ec.europa.eu/efda/tl-browser. If absent, switch to a verified qualified provider.

Reason 7 — Technical INPI bug (4% of cases)

Sometimes, the Guichet Unique is just buggy: temporary outage, browser cache, server overload at peak times.

Fix: try in private browsing, clear browser cache, retry an hour later. If persistent, call INPI support: 0820 210 211.

INPI summary rejected? Re-sign in 2 minutes.

Qualified eIDAS signature via Universign, 100% accepted by the INPI Guichet Unique. €29 ex. VAT.

Sign my summary →

How to identify the exact rejection cause

The Guichet Unique sometimes shows generic messages. To dig deeper:

  1. Note the exact error message: take a screenshot.
  2. Open the signed PDF in Adobe Reader: click the signature, "Signature properties". Verify level (must be QES qualified) and issuer (must be on EU Trust List).
  3. Verify the hash: re-download the original from the Guichet Unique and compare its size/date with what you signed.
  4. Check the signer: are you the legal representative of the entity for this formality?
  5. Contact INPI support: 0820 210 211 to know the exact cause if the message is unclear.

Re-signing: how to avoid wasting time

Once the cause is identified, the fix takes 5 minutes max:

  1. Re-download the original PDF from the Guichet Unique (without opening it elsewhere).
  2. Drop it on SignerSynthèse.fr or another qualified provider.
  3. Pay €29 ex. VAT (one-time, no subscription).
  4. Verify your identity by ID photo + selfie + SMS.
  5. Receive the signed PDF by email.
  6. Upload it back to the Guichet Unique.

Total time: 2 to 5 minutes. The formality is validated instantly.

Conclusion

An INPI summary rejection is almost always solvable in less than 5 minutes once the cause is identified. The qualified signature level is the #1 cause: don't try to optimise on advanced or simple, take qualified directly. The €29 ex. VAT cost is largely worth it compared to lost time and risk of late penalties.

Official sources