What is electronic signature? Complete guide 2026
Updated on
Electronic signature (or e-signature) allows you to sign documents digitally with the same legal value as a handwritten signature. This guide explains how it works, the three levels defined by eIDAS regulation, its legal validity in France and Europe, and how to implement electronic signature in your organisation.
In brief
- Legal value = handwritten signature (art. 1367 Civil Code + eIDAS EU regulation 910/2014)
- 3 recognised levels: Simple (SES), Advanced (AES) and Qualified (QES)
- Valid in all 27 EU Member States — direct application without transposition
- How it works: signer identification + cryptographic fingerprint (hash) of the document
- Average ROI < 3 months — contract finalised in hours vs. 5 days by post
Definition: what is electronic signature?
A electronic signature is a set of data in electronic form which are attached to or logically associated with other data in electronic form and which the signatory uses to sign. This definition, taken from eIDAS regulation (regulation (EU) No. 910/2014), covers a wide spectrum of technical mechanisms, from the simplest (ticking a box, typing your name) to the most sophisticated (qualified cryptographic certificate).
Under French law, article 1367 of the Civil Code provides that "the signature necessary for the completion of a legal act identifies the person who apposes it" and that, when it is electronic, it "consists in the use of a reliable identification procedure guaranteeing its link with the act to which it attaches". The reliability of the procedure is presumed for signatures qualified within the meaning of eIDAS.
Concretely, an electronic signature fulfils three functions: it identifies the signatory, it expresses their consent to the content of the document, and it guarantees the integrity of the document (any modification after signature is detectable).
Electronic signature vs digital signature
The terms are often confused. Electronic signature is the legal concept (what commits the signatory). Digital signature is the underlying cryptographic technique (document hash, asymmetric encryption with private key) which can be used to implement an advanced or qualified electronic signature. Every digital signature is an electronic signature, but the reverse is not true.
How does electronic signature work?
The mechanism rests on two pillars: the authentication of the signer and the integrity of the document.
To authenticate the signatory, one or more identification factors are used: trusted email address (single-use link), OTP code received by SMS, personal cryptographic certificate, etc. To guarantee integrity, a fingerprint (hash) of the document is calculated at the time of signature. If the document is subsequently modified, the fingerprint no longer matches — the signature is then invalidated.
In solutions like Certyneo, the process relies on PDF processing libraries that integrate these cryptographic metadata directly into the file. A timestamped audit trail (action log) completes the system by recording each step: sending, opening, OTP validated, signature, etc.
On the technical side, several security mechanisms reinforce the inviolability of the process: qualified timestamping (RFC 3161) applies certified time proof to each signature; TLS 1.3 encryption protects data in transit; the signatory's geolocation and IP address are recorded for traceability; finally, in certain flows (AES/QES), behavioural biometric data (typing speed, pressure) complements the identity fingerprint.
The concept of non-repudiation is central: thanks to the timestamped and cryptographically signed audit trail, it is technically impossible for a signatory to deny signing a document without falsifying the chain of evidence. For archiving purposes, French regulation (Decree 2016-1673) requires a retention period of 10 years for most business documents — Certyneo ensures this archiving with probative value in sovereign hosting (EU).
The 3 levels of electronic signature according to eIDAS
The eIDAS regulation defines a hierarchy of three levels. The higher the level, the stronger the identification requirements and the more robust the legal presumption.
Simple Signature
Simple Electronic Signature
Examples
Web form, checkbox, typed name
Typical use cases
Quotations, internal orders, low-risk documents
Certyneo
Available on all Certyneo plans
Advanced Signature
Advanced Electronic Signature
Examples
SMS OTP + email, strong signer authentication
Typical use cases
Employment contracts, NDAs, significant commercial contracts
Certyneo
Standard and Business plans — dual-channel OTP (email + SMS)
Qualified Signature
Qualified Electronic Signature
Examples
QTSP certificate + secure creation device
Typical use cases
Notarial deeds, high-value contracts, public procurement
Certyneo
Via partner QTSP on request — native integration on roadmap
eIDAS 3-level comparison table
| Criterion | SES — Simple | AES — Advanced | QES — Qualified |
|---|---|---|---|
| Signer identification | Email only | OTP SMS + email | QTSP + QSCD certificate |
| Document integrity | Basic | Cryptographic (hash) | Cryptographic (hash) |
| Qualified certificate required | No | No | Yes (eIDAS provider) |
| Presumption of handwritten equivalence | No | Partial | Full (art. 25 eIDAS) |
| Burden of proof reversal | No | No | Yes (in favour of the signatory) |
| Typical use case | Quotations, orders | HR contracts, NDA, employment agreements | Public deeds, public procurement |
| Certyneo availability | All plans | Standard and Business | Via partner QTSP |
Key legal point — reversal of the burden of proof: For QES only, article 25 of eIDAS regulation establishes a legal presumption of equivalence with handwritten signature. In the event of dispute, it is for the challenger to prove that the signature is invalid — not for the signatory to prove its validity. This reversal is a considerable advantage in contractual disputes.
Legal validity in France and the European Union
In France, electronic signature has been recognised since law No. 2000-230 of 13 March 2000, which amended the Civil Code to establish electronic writing and electronic signature as equivalent to their paper counterparts. Article 1366 specifies that electronic writing "has the same probative force as writing on paper support".
At European level, the eIDAS regulation (EU) No. 910/2014 creates a unified legal framework for electronic signatures. Its article 25 establishes the principle of non-discrimination: "electronic signature shall not be refused legal effect and admissibility as evidence in legal proceedings on the sole ground that it is in electronic form". Qualified signatures (QES) also benefit from a legal presumption equivalent to a handwritten signature in all 27 Member States.
For standard documents (commercial contracts, employment contracts, quotations, NDA, mandates), an advanced signature (AES) offers an excellent balance between ease of use and legal certainty. Qualified signature (QES) is reserved for high-value acts or situations where sectoral regulation explicitly requires it.
French reference texts
- Article 1366 of the French Civil Code (electronic writing)
- Article 1367 of the French Civil Code (electronic signature)
- Decree No. 2017-1416 of 28 September 2017 (reliability presumption)
European reference texts
- Regulation (EU) No. 910/2014 (eIDAS)
- Directive 1999/93/EC (repealed, previous framework)
- eIDAS Regulation 2.0 (2024 — digital identity wallet)
To ensure a service provider's compliance, ANSSI publishes the French Trust List (TSL — Trust Service List) of qualified providers authorised to issue QES certificates. At European level, each Member State publishes its own TSL, all accessible via the European Commission's official portal (eidas.ec.europa.eu). Certyneo is ISO 27001 certified and hosts its data in the EU (Germany).
The benefits of electronic signature for businesses
Beyond legality, electronic signature fundamentally transforms contractual and administrative processes.
Time saving
Un contrat qui prenait 5 jours (impression, envoi postal, retour) se finalise en quelques heures. Les rappels automatiques éliminent les relances manuelles.
Enhanced security
L'audit trail horodaté, le chiffrement TLS 1.3 et l'OTP double canal offrent un niveau de preuve supérieur au papier contre la falsification ou le déni.
Legal validity
eIDAS compliance and article 1367 of the Civil Code. Signed documents have the same probative force as a handwritten signature and are admissible in French courts.
Cost reduction
Élimination des coûts d'impression, d'envoi, d'archivage physique et de gestion manuelle. Le ROI est généralement atteint en moins de 3 mois.
Complete traceability
Every step in the document lifecycle is recorded. You know exactly who opened, read and signed, and when, from which IP address.
GDPR compliance
Data hosted in Germany (EU), documented retention period, right of access and erasure. GDPR compliance is built in natively.
Which documents and sectors can use electronic signature?
Almost all contracts and legal deeds can be electronically signed. A few exceptions remain (notarial deeds, handwritten wills) but they affect less than 5% of common business transactions.
Human Resources
- Employment contracts (permanent, fixed-term, apprenticeship)
- Amendments and job modifications
- Internal regulations, charters
- Employee confidentiality agreements (NDA)
Legal and Commercial
- NDA (non-disclosure agreements)
- Service and contractor agreements
- Purchase orders and quotations
- Rights assignment contracts
Real Estate
- Sale and management mandates
- Residential and commercial leases
- Sale agreements (excluding authentic deeds)
- Condition reports
Finance and Banking
- Account openings and KYC
- SEPA direct debit mandates
- Loan agreements (excluding notarised mortgage credit)
- Terms and conditions and amendments
Excluded documents (require authentic deeds)
- ×Final property sales (notarial deed mandatory)
- ×Handwritten wills
- ×Marriage and divorce certificates (official records)
- ×Certain secured interest deeds (mortgages)
5 common mistakes with electronic signature (and how to avoid them)
Even if legally recognised, an electronic signature can be contested if poorly implemented. Here are the most frequent pitfalls observed in business.
Using a level too low for the contract
Signing an employment contract or transfer deed with SES (simple click) exposes the employer to contestation risk. Rule: any contract worth > €1,500 or with significant HR consequences must use at least AES with SMS OTP.
Ignoring the audit trail (proof log)
The signed document is only part of the proof. The audit trail — which documents each step (send, open, OTP validated, time, IP) — is the cornerstone in case of dispute. Without it, it is impossible to reconstruct the chain of events before a judge.
Failing to verify the provider's GDPR compliance
Biometric and identification data of signatories are sensitive personal data. Your provider must host data in the European Union and have a GDPR-compliant DPA (Data Processing Agreement). Beware of US-based solutions without EU hosting.
Confusing electronic signature and digitised signature
Scanning your handwritten signature and inserting it into a PDF has no legal value within the meaning of eIDAS regulation. A real electronic signature is based on cryptographic mechanisms of integrity and authentication — not on an image.
Neglecting long-term archiving
Decree 2016-1673 requires retaining signature evidence for the entire legal lifetime of the contract (10 years for commercial acts, 5 years for employment contracts). Your solution must guarantee probative archiving, not just standard cloud storage.
How to implement electronic signature: step-by-step guide
With Certyneo, you can send your first document for signature in less than 5 minutes.
Create your account
Sign up to Certyneo in seconds with your email or via Google/Microsoft. No payment card required to get started.
Upload your document
Import your PDF or Word file. Certyneo automatically converts Word files to an optimised PDF for signature.
Add signatories
Enter the name and email of each signatory. Define the signing order if necessary and position the signature fields in the document.
Send the envelope
A secure email is sent to each signatory with a unique link. For advanced signature, the signatory also receives an OTP via SMS.
Track in real-time
From your dashboard, track the status of each envelope: sent, opened, signed or declined. Automatic reminders re-engage inactive signatories.
Archive the final document
Once all signatories have signed, the final PDF (with integrated audit footer) is automatically archived for 10 years and accessible at any time.
Frequently asked questions about electronic signature
What is an electronic signature?
An electronic signature is a technical process for identifying the author of a digital document and guaranteeing the integrity of that document. It is the legal equivalent of a handwritten signature within the meaning of eIDAS regulation (EU) No. 910/2014 and article 1367 of the French Civil Code.
Is electronic signature legal in France?
Yes. Electronic signature has been legally recognised in France since the law of 13 March 2000 (article 1367 of the Civil Code) and throughout the European Union through eIDAS regulation. It has the same legal value as a handwritten signature provided the conditions for identification of the signatory and integrity of the document are met.
What is the difference between simple, advanced and qualified signature?
eIDAS defines three levels. Simple signature (SES) corresponds to the basic level: clicking, ticking a box or typing your name. Advanced signature (AES) requires identification of the signatory (OTP SMS/email, for example) and a unique link with the document. Qualified signature (QES) additionally requires a certificate issued by a qualified trust service provider (QTSP) and a secure signature creation device — it offers the strongest legal presumption.
What documents can be signed electronically?
Almost all contractual and commercial documents can be signed electronically: employment contracts, quotes and purchase orders, NDAs, service contracts, amendments, mandates, agreements, assignment deeds. Certain formal acts (notarial deeds, civil status records) require specific conditions.
How does Certyneo electronic signature work?
With Certyneo, the sender uploads their PDF document, adds signatories and defines fields. Each signatory receives a secure link by email. For advanced signature (AES), a dual OTP email + SMS (our SMS OTP provider) authenticates the signatory. The final PDF includes a timestamped audit footer and is archived for 10 years.
Is electronic signature valid throughout the EU?
Yes. eIDAS regulation applies directly in the 27 EU Member States. A qualified signature issued in one member country is recognised in all other member states. Simple and advanced signatures also have probative value but may be subject to assessment by the judge.
How much does electronic signature cost with Certyneo?
Certyneo offers a free plan (5 envelopes/month), a Personal plan at £9/month, a Standard plan at £19/month and a Business plan at £39/month (Business) or £99/month (Business Pro). Advanced eIDAS signature (AES) is available from the Personal plan (£9/month) onwards.
What is an audit trail and what is it for?
The audit trail is a timestamped log of all actions performed on an envelope: sending, opening, viewing, signing, declining, expiry. It provides evidence of the chronology of events and strengthens the probative value of the signed document in the event of a dispute.
Is electronic signature really secure?
Yes, an electronic signature compliant with eIDAS is technically safer than a handwritten signature. It combines: (1) signatory identification by OTP SMS or certificate, (2) cryptographic fingerprint (SHA-256 hash) of the document — any post-signature modification immediately invalidates the signature, (3) qualified timestamping certifying the exact time, (4) signed and encrypted audit trail preserving the complete history. None of these protections exist for a paper signature.
How long should electronically signed documents be retained?
The retention period depends on the nature of the document: 10 years for commercial contracts (art. L.110-4 French Commercial Code), 5 years for employment contracts, 30 years for real estate deeds. Decree 2016-1673 requires that archiving be carried out under conditions guaranteeing document integrity and readability. Certyneo provides such archiving with probative value hosted in the European Union.
What is non-repudiation and why is it important?
Non-repudiation is the legal and technical property that prevents a signatory from denying that they appended their signature. It is guaranteed by the combination of: the timestamped and cryptographically signed audit trail, the OTP sent to the signatory''s telephone number (proof of possession), and the unique fingerprint of the document. In the event of judicial dispute, non-repudiation constitutes a strong presumption in favour of the signature beneficiary.
What certifications and compliance standards should you check with a service provider?
For a reliable and compliant solution, verify: eIDAS qualification (ANSSI trust list for QES), ISO 27001 certification (information security), GDPR compliance with EU hosting, HDS compliance if you process health data, and ideally ANSSI's SecNumCloud qualification for cloud-hosted solutions. Certyneo hosts all its data in Germany (EU).
Certyneo Legal Team
Electronic signature and contract law experts
This guide is written and maintained by Certyneo's legal and technical team, specialising in electronic contract law, eIDAS compliance and data protection (GDPR). Each article is reviewed quarterly to reflect the latest regulatory developments.
- Expertise in eIDAS Regulation (EU) no. 910/2014
- GDPR compliance and hosting within the European Union
- Processing of over 50,000 electronically signed documents
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