What is an 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 manuscript 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 = manuscript signature (art. 1367 French Civil Code + EU eIDAS regulation 910/2014)
- 3 recognised levels: Simple (SES), Advanced (AES) and Qualified (QES)
- Valid in all 27 EU Member States — direct application without transposition
- Operation: signer identification + cryptographic fingerprint (hash) of the document
- Average ROI < 3 months — contract finalised in hours vs. 5 days by post
Definition: What is an electronic signature?
A electronic signature is a set of data in electronic form, which are attached or logically associated with other data in electronic form and which the signer uses to sign. This definition, taken from the eIDAS regulation (regulation (EU) No. 910/2014), covers a wide spectrum of technical mechanisms, from the simplest (checking a box, typing your name) to the most sophisticated (qualified cryptographic certificate).
In French law, article 1367 of the Civil Code provides that "the signature necessary for the perfection of a legal act identifies the person who affixes it" and that, when it is electronic, it "consists in the use of a reliable identification process guaranteeing its link with the act to which it attaches". The reliability of the process is presumed for signatures qualified under eIDAS.
In practice, an electronic signature fulfils three functions: it identifies the signatory, it expresses their consent to the contents of the document, and it guarantees the integrity of the document (any modification after signing is detectable).
Electronic signature versus digital signature
The terms are often confused. Electronic signature is the legal concept (what commits the signer). 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 hash (fingerprint) of the document is calculated at the time of signing. If the document is modified afterwards, the hash 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 (log of actions) completes the system by recording each step: sending, opening, OTP validated, signature, etc.
From a technical perspective, several security mechanisms strengthen the inviolability of the process: qualified timestamping (RFC 3161) applies certified time-proof to each signature; TLS 1.3 encryption protects data in transit; geolocation and the signatory's IP address are recorded for traceability; finally, in certain flows (AES/QES), behavioural biometric data (typing speed, pressure) complement 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 having signed a document without falsifying the chain of evidence. With respect to archiving, French regulations (Decree 2016-1673) require retention for 10 years for most commercial acts — 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, name typed on keyboard
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
Notarised deeds, very high-value contracts, public procurement
Certyneo
Via QTSP partner on request — native integration in roadmap
Comparative table of 3 eIDAS levels
| 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 Equivalence to Handwritten Signature | No | Partial | Full (art. 25 eIDAS) |
| Reversal of Burden of Proof | No | No | Yes (in favour of the signatory) |
| Typical Use Cases | Quotations, orders | HR contracts, NDAs, employment agreements | Notarised deeds, public procurement |
| Certyneo Availability | All plans | Standard and Business | Via partner QTSP |
Key legal point — reversal of burden of proof: For QES only, article 25 of eIDAS regulation establishes a legal presumption of equivalence with manuscript signature. In case of dispute, it is for the challenger to prove that the signature is invalid — not for the signer 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, eIDAS regulation (EU) No. 910/2014 creates a unified legal framework for electronic signatures. Its article 25 establishes the principle of non-discrimination: "an electronic signature cannot be denied legal effects and admissibility as evidence in legal proceedings solely on the grounds that it is in electronic form". Qualified signatures (QES) also benefit from a legal presumption equivalent to a manuscript signature in the 27 member states.
For standard documents (commercial contracts, employment contracts, quotes, NDAs, mandates), an advanced signature (AES) offers an excellent balance between ease of use and legal security. Qualified signature (QES) is reserved for high-value documents or situations where sector-specific regulations explicitly require 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 (presumption of reliability)
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 the European level, each Member State publishes its own TSL, all accessible via the official European Commission 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 savings
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 value
eIDAS compliance and article 1367 of the French Civil Code. Signed documents have the same probative force as a manuscript signature and are admissible before 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 of the document's lifecycle is recorded. You know exactly who opened, read and signed, and at what time, from which IP address.
GDPR compliance
Data hosted in Germany (EU) (European Union), documented retention period, right of access and deletion. GDPR compliance is included natively.
What documents and sectors can use electronic signature?
Nearly all contracts and legal documents can be electronically signed. Few exceptions remain (notarial deeds, handwritten wills) but they account for less than 5% of common commercial documents.
Human Resources
- Employment contracts (permanent, fixed-term, apprenticeship)
- Amendments and job modification letters
- Internal regulations and employee charters
- Employee confidentiality agreements (NDA)
Legal and Commercial
- Non-disclosure agreements (NDA)
- Service and supply contracts
- Purchase orders and quotations
- Intellectual property assignment contracts
Real Estate
- Sales and management mandates
- Residential and commercial leases
- Sales agreements (excluding authentic deeds)
- Property condition reports
Finance and Banking
- Account opening and KYC
- SEPA direct debit mandates
- Loan agreements (excluding notarised mortgage loans)
- Terms and conditions and amendments
Excluded documents (require authentic deed)
- ×Definitive property sales (notarial deed required)
- ×Handwritten wills
- ×Marriage and divorce certificates (civil deed)
- ×Certain security interests (mortgage)
5 common mistakes with electronic signature (and how to avoid them)
Even if legally recognised, an electronic signature can be challenged if poorly implemented. Here are the most frequent pitfalls observed in business.
Using too low a level for the contract
Signing an employment contract or deed of transfer with SES (simple click) exposes the employer to a risk of challenge. Rule: any contract worth > €1,500 or with significant HR consequences must use at minimum 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 service provider's GDPR compliance
Biometric and identification data of signatories are sensitive personal data. Your service provider must host data in the European Union and have a DPA (Data Processing Agreement) compliant with GDPR. Beware of US-based solutions without EU hosting.
Confusing electronic signature and scanned signature
Scanning your manuscript signature and inserting it into a PDF has no legal value under eIDAS regulation. A true electronic signature is based on cryptographic mechanisms for integrity and authentication — not on an image.
Neglecting long-term archiving
Decree 2016-1673 requires preserving signature evidence for the entire legal lifetime of the contract (10 years for commercial documents, 5 years for employment contracts). Your solution must guarantee archiving with probative value, not just standard cloud storage.
How to implement electronic signature: step-by-step guide
With Certyneo, you can send your first document to sign in less than 5 minutes.
Create your account
Sign up on Certyneo in seconds with your email or via Google/Microsoft. No credit card required to get started.
Upload your document
Import your PDF or Word file. Certyneo automatically converts Word files to PDF optimised for signing.
Add signatories
Enter the name and email of each signatory. Set 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 rejected. Automatic reminders follow up with 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 manuscript signature under eIDAS regulation (EU) No. 910/2014 and article 1367 of the French Civil Code.
Is electronic signature legal in France?
Yes. Electronic signature is legally recognised in France since the law of 13 March 2000 (article 1367 of the Civil Code) and throughout the European Union thanks to eIDAS regulation. It has the same legal value as a manuscript signature as long as the conditions for identification of the signer 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: click, check a box or type your name. Advanced signature (AES) requires identification of the signer (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, quotations and purchase orders, NDAs, service contracts, amendments, mandates, agreements, transfer deeds. Certain authentic acts (notarial deeds, civil status acts) require specific conditions.
How does Certyneo's electronic signature work?
With Certyneo, the sender uploads their PDF document, adds the signatories and defines the 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 incorporates a timestamped audit footer and is archived for 10 years.
Is electronic signature valid throughout the EU?
Yes. eIDAS is directly applicable in the 27 member states of the European Union. 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 court.
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).
What is an audit trail and what is it for?
The audit trail is a timestamped log of all actions performed on an envelope: send, open, view, sign, reject, expire. It provides evidence of the chronology of events and strengthens the evidential value of the signed document in case of dispute.
Is electronic signature really secure?
Yes, an eIDAS-compliant electronic signature is technically safer than a manuscript signature. It combines: (1) signer identification via OTP SMS or certificate, (2) cryptographic fingerprint (SHA-256 hash) of the document — any post-signature modification immediately invalidates the signature, (3) qualified time-stamping certifying the exact time, (4) signed and encrypted audit trail preserving complete history. None of these protections exist for a paper signature.
How long must electronically signed documents be kept?
The duration 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 property matters. Decree 2016-1673 requires archiving to be carried out under conditions guaranteeing document integrity and readability. Certyneo ensures such archiving with evidential 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 signer from denying having affixed their signature. It is guaranteed by the combination of: the time-stamped audit trail and cryptographically signed, the OTP sent to the signer''s phone number (proof of possession), and the unique fingerprint of the document. In case of judicial dispute, non-repudiation constitutes a strong presumption in favour of the signature beneficiary.
What certifications and compliance standards should be checked 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 hosting in the EU, 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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