When trying to sign an INPI formality, the first reaction is: "Is there a free way?" The honest answer: almost everything free is unusable, because the Guichet Unique requires an eIDAS qualified signature, the highest level of EU Regulation 910/2014. This level can only be produced by a Qualified Trust Service Provider, and these providers charge for their service.
This article reviews, one by one, the "free" solutions users regularly try, and explains why they fail. The only legitimate exception — FranceConnect+ — also has hidden limits.
Why free signature almost never works with INPI
eIDAS Regulation 910/2014 defines 3 levels of electronic signature:
- Simple signature: a click, a tickbox, a scanned image. No strong identity check. Cost: €0. Refused by INPI.
- Advanced signature: identity verified but not by a qualified provider. Cost: €0 to €5. Refused by INPI.
- Qualified signature: identity verified via PVID + certificate from a Qualified Trust Service Provider listed on the EU Trust List. Cost: impossible at €0 (the provider has infrastructure and ANSSI compliance costs). The only level accepted by INPI.
The Guichet Unique automatically checks the cryptographic level of the signed PDF. If it's below "qualified", it's rejected with a generic message "Signature non conforme".
The "free" pseudo-solutions to avoid
1. Adobe Acrobat Reader (handwritten scanned signature)
You open the PDF summary in Adobe Reader, click "Fill & Sign", trace your signature with the mouse or insert a scan. It's a simple signature. No legal value within eIDAS. Immediately rejected by INPI.
Worse: opening the PDF in Adobe Reader then saving it, even without visible modification, can alter metadata and invalidate a future qualified signature if you decide to re-sign correctly.
2. Yousign Free / DocuSign Free / other free plans
Yousign and DocuSign offer free plans limited to 5 or 3 signatures per month. These signatures are simple level only. For qualified eIDAS signature, you must move to a paid plan (€300 to €600 ex. VAT/year minimum). See pricing comparison.
3. Handwritten signature printed and scanned
You print the PDF, sign with a pen, scan. No electronic value. The PDF is no longer original (it's an image), the signature is neither verifiable nor traceable, and the format doesn't match what the Guichet Unique expects. Guaranteed rejection.
4. Simple electronic signature via free online tools
Sites like SmallPDF, iLovePDF, SignWell.com offer free electronic signatures. Always simple level. For commercial contracts between private parties, that's enough; for INPI, useless.
5. Non-qualified advanced signature
Some cheap providers sell an "advanced signature" (sometimes marketing-disguised as "secure electronic signature") for a few euros. The INPI Guichet Unique requires the qualified level, not advanced. See advanced vs qualified eIDAS signature.
The only free signature passing INPI: FranceConnect+ via La Poste Digital Identity
The French State funded a national digital identity infrastructure that, in fine, produces free qualified eIDAS signatures. The service is called FranceConnect+ and relies on the La Poste Digital Identity app.
How it works
- Install the La Poste Digital Identity app on your smartphone.
- Make a post office appointment for physical certification (face-to-face identity verification).
- Get a certified level account (equivalent to "substantial" in eIDAS, which can produce qualified signatures in some cases).
- On the INPI Guichet Unique, click "Sign with FranceConnect+", validate on the La Poste app, the PDF is qualified-signed.
Real cost
Officially free. In reality:
- 1 physical visit to a post office (15-30 min of your time + travel).
- 2 to 5 working days between appointment booking and effective certification.
- Risk of FranceConnect+ outage when signing: blank page, orange banner, infinite loop. Statistically, about 1 in 5 users hits an outage on first try.
If you value your time at €50/hour and you need 2 hours (between appointments, travel, failed attempts and retries), you have "paid" €100 of time. The service is technically free but expensive.
No time for FranceConnect+? €29 ex. VAT, 2 minutes.
Qualified eIDAS signature via Universign (EU Trust List), delivered by email. 100% accepted by the INPI Guichet Unique.
Sign my summary →Recap table: what works?
| Solution | Cost | Level | INPI accepted? |
|---|---|---|---|
| Adobe Reader (handwritten scan) | €0 | Simple | ❌ NO |
| Yousign / DocuSign free plan | €0 | Simple | ❌ NO |
| Pen signature scan | €0 | None | ❌ NO |
| SmallPDF / iLovePDF / SignWell | €0 | Simple | ❌ NO |
| Low-cost advanced signature | €5-15 | Advanced | ❌ NO |
| FranceConnect+ via La Poste Digital Identity | €0 (but time) | Qualified | ✅ YES |
| Pay-as-you-go qualified provider (SignerSynthèse.fr) | €29 ex. VAT | Qualified | ✅ YES |
FAQ
Can INPI accept a free electronic signature?
Yes, but only if it's qualified eIDAS level. The only legitimate free route is FranceConnect+ via certified La Poste Digital Identity. Any other free signature (Adobe, Yousign Free, etc.) is rejected.
Why is my Adobe Reader-signed PDF rejected?
Adobe Reader produces a simple signature, sometimes labeled "certified" in its interface, but which doesn't meet the eIDAS qualified standard. The Guichet Unique checks the issuer certificate: if it's not a provider listed on the EU Trust List, automatic rejection.
Is there a free way for micro-entrepreneurs?
No. Legal status (micro-enterprise, SAS, SARL) has no impact on the required signature level. Everything depends on the type of formality (articles amendment, cessation, accounts, etc.). See company formation.
How long to get a certified La Poste Digital Identity?
2 to 5 working days. Includes: appointment booking (1-2 days wait), post office visit (15-30 min on site), account activation (immediate after verification).
Can my company reimburse the €29 ex. VAT?
Yes, it's a deductible expense. You receive a professional invoice after payment at SignerSynthèse.fr.
Conclusion
"Free" electronic signature for INPI is essentially a marketing myth. The only truly free route is FranceConnect+, which requires a prior physical visit and regularly crashes at the worst moment. For an urgent or one-off formality, paying €29 ex. VAT for a pay-as-you-go qualified signature is far more profitable than wasting half a day.
If you insist on the free route, plan 1 week between creating your La Poste Digital Identity and effectively signing your formality. Otherwise, the pay-as-you-go qualified provider option is for you.