Real Estate Purchase Agreement & Electronic Signature

What the Law Says About Electronic Signature of a Purchase Agreement

The Legal Value of Electronic Writing Under French Law

Since the law of March 13, 2000, codified in articles 1366 and 1367 of the French Civil Code, electronic writing is recognized as equivalent to paper writing, subject to two cumulative conditions: reliable identification of the person from whom it emanates, and guarantee of the document's integrity. The real estate purchase agreement, which constitutes in French law a bilateral preliminary contract binding both parties irrevocably subject to suspensive conditions, can therefore perfectly be concluded in electronic form.

However, the nature of this act requires particular precautions. A purchase agreement is not a simple purchase order: it can commit sums of several hundred thousand euros and must satisfy strict pre-contractual information obligations (Alur law, Macron law, mandatory building diagnostics). The robustness of the signature used directly conditions its probative value in case of dispute.

The Three Levels of eIDAS Signature Applied to Real Estate

Regulation eIDAS No. 910/2014 distinguishes three levels of electronic signature, whose relevance varies depending on the type of real estate act:

Simple Electronic Signature (SES): sufficient for information documents or low-value search mandates, it is generally insufficient for a purchase agreement due to the high risk of contestation.

Advanced Electronic Signature (AES): this is the level recommended by professional practice for purchase agreements under private deed. It is based on strong authentication of the signatory (generally via an OTP code sent to the mobile phone and documentary identity verification). It allows unique identification of the signatory, detection of any document alteration after signature, and commitment of the signatory's liability.

Qualified Electronic Signature (QES): mandatory for notarized authentic acts, it is based on a qualified certificate issued by a trust service provider (TSP) appearing on the European Trust List. For electronic authentic acts (EAA), notaries have had since 2008 a specific qualified signature creation device, managed by the Higher Council of Notaries (CSN) through the REAL infrastructure (Electronic Network of Authorities and Notaries).

Private Deed Purchase Agreement vs. Authentic Act: Two Distinct Regimes

It is crucial to distinguish between two legally different situations:

The purchase agreement under private deed, drafted and signed directly between individuals or through a real estate professional (real estate agent, notary in simple advisory capacity), can be signed with an advanced electronic signature. No law requires qualified signature here for ordinary properties (except for sales in the state of future completion – VEFA – or certain properties subject to special regimes).

The unilateral promise of sale (or promise to purchase), when registered with the tax administration within ten days (article 1589-2 of the French Civil Code, under penalty of nullity for certain promises), requires particular attention: registration can be carried out in dematerialized form, but the authenticity of the signature must be unquestionable.

The authentic deed of sale (final deed signed at the notary's office) mandatorily requires the qualified electronic signature of the notary, in accordance with Decree No. 2005-973 of August 10, 2005, and subsequent texts relating to the electronic authentic act.

The Central Role of the Notary in Real Estate Electronic Signature

The Electronic Authentic Act (EAA): A Silent Revolution

Since 2008, French notaries have been able to draw up fully dematerialized authentic acts. In 2025, more than 95% of real estate sales acts at notaries are drawn up in electronic form according to CSN data. The electronic authentic act (EAA) presents major advantages: enhanced probative force, enforceability against third parties, secure preservation in the CENTRAL MINUTIER system (central digital archiving).

The notary affixes his qualified electronic signature using a personal encrypted USB key and PIN code. This signature is based on a qualified certificate issued by the chamber of notaries, compliant with the requirements of standard ETSI EN 319 132 for XAdES signatures, or CAdES/PAdES depending on the document format.

Remote Appearance: Notarial Remote Signing

The ELAN law of November 23, 2018 (article 20) and Decree No. 2020-395 of April 3, 2020 legalized in France remote appearance before a notary, also called "remote notarized act" or "remote signing". This procedure allows the buyer and/or seller to sign the authentic act without physically traveling to the notary's office, via a secure videoconference platform approved by the CSN.

Concretely: the notary is present in the office, the client(s) appear remotely via video. Identity verification is performed in real time, and signatures are affixed electronically via a secure process. This advancement has considerably streamlined transactions, particularly for buyers residing abroad or in distant regions.

Signature of the Purchase Agreement at the Real Estate Agent's Office or Online

In current practice, the purchase agreement is frequently signed at the real estate agent's office or online, outside any notarial framework. In this case, SaaS electronic signature platforms like Certyneo for real estate play a decisive role: they must guarantee:

• Identity verification compliant with eIDAS (documentary verification + facial liveness for advanced levels)
• Qualified timestamping of the signed document
• Complete audit trail (logs, IP addresses, document fingerprints)
• Secure preservation of signature evidence

The complete guide to electronic signature details the technical criteria to verify when choosing your solution.

Practical Procedure: Sign a Purchase Agreement Online Step by Step

Prepare the Documentary File

Before any signature, the seller must constitute the technical diagnostic file (DDT) comprising in particular: the energy performance certificate (DPE), the lead exposure risk statement (CREP) if the property predates 1949, the statement of the condition of interior electrical and gas installations if they are more than 15 years old, the statement of risks and pollution (ERP), and the asbestos diagnostic for construction permits prior to July 1997.

These documents must be appended to the purchase agreement and integrated into the documentary envelope submitted for electronic signature. A professional platform must allow the signature of multi-page documents with appendices, and generate a single probative file including the entire file.

The Electronic Signature Journey

An advanced electronic signature journey for a purchase agreement generally follows these steps:

1. Upload and preparation: the professional imports the purchase agreement and its appendices on the platform, places signature and initial zones page by page.
2. Invitation of signatories: buyer(s) and seller(s) receive a secure link by email.
3. Identity verification: depending on the signature level, the signatory uploads an identity document and performs a selfie or dynamic facial recognition.
4. Reading and initialing: the signatory reviews the document, affixes initials on each page (or accepts automatic scrolling).
5. OTP Code: a one-time code is sent by SMS to the verified phone number of the signatory.
6. Signature affixing: the signature is cryptographically linked to the document, timestamped, and recorded with the audit trail.
7. Archiving: all parties receive a copy of the signed purchase agreement in PDF/A format with its proof report.

Withdrawal Period and Electronic Signature

The SRU law (article L. 271-1 of the Building and Housing Code) grants non-professional buyers a withdrawal period of 10 calendar days from the notification of the preliminary contract. In the context of electronic signature, this notification can be carried out in dematerialized form (registered electronic mail or traceable secure sending), provided that the acknowledgment of receipt is probative and timestamped. The signature platform must therefore integrate a certified electronic registered mail sending functionality in compliance with standard ETSI EN 319 532.

Note that the period runs from the day following the first presentation of the registered letter, not from its signature. Choosing an integrated solution simultaneously managing signature and certified electronic notification considerably simplifies this critical step.

Choosing the Right Electronic Signature Solution for Real Estate

Platform Selection Criteria

Given the proliferation of offerings on the market (DocuSign, Yousign, Universign, Certyneo and others), real estate professionals must evaluate platforms on specific criteria:

Regulatory compliance: the platform must be certified by an accredited body (ANSSI, BSI, LSTI…) and appear or rely on TSPs appearing on the EU Trusted List. Verify ISO 27001 certifications, advanced and/or qualified eIDAS levels according to your needs.

User experience: in real estate, signatories are often individuals unfamiliar with electronic signature. The journey must be intuitive, available on mobile, and accompanied by contextual assistance.

Industry integrations: ideally, the solution integrates with your real estate management software (Périclès, Immofacile, iadmin, Apimo…) via REST API or native connectors.

Probative archiving: beyond signature, secure preservation of signed documents for legal periods (30 years for a sales deed) is a major issue. Some platforms offer an integrated digital safe compliant with standard NF Z 42-020.

Support and SLA: for transactions with high financial stakes, support availability (ideally 7 days/week) and availability SLA greater than 99.9% are prerequisites.

To objectively compare market solutions, consult our comparison of electronic signature solutions.

ROI of Electronic Signature in Real Estate Agency

Adoption of electronic signature generates measurable gains for real estate professionals:

• Reduction in signature delay: a traditional purchase agreement requires on average 5 to 10 days of coordination to bring parties together; electronic signature reduces this delay to 24-48 hours in the majority of cases.
• Decrease in logistics costs: printing, certified postal sending, physical archiving represent between 15 and 30 € per file depending on agencies.
• Reduction in incomplete file rate: platforms require completion of all required fields before signing, eliminating oversights of initials or signatures on certain pages.
• Improved customer experience: the ability to sign from home or office without travel is a differentiating commercial argument.

Calculate your personalized return on investment with our electronic signature ROI calculator.

Applicable Legal Framework for Electronic Signature of Real Estate Purchase Agreements

Founding Texts

French Civil Code, articles 1366 and 1367: these two articles constitute the foundation of French law on electronic evidence. Article 1366 states that "electronic writing has the same probative force as writing on paper, provided that the person from whom it emanates can be duly identified and that it is established and preserved in conditions likely to guarantee its integrity". Article 1367 clarifies the conditions for validity of electronic signature: reliability of signatory identification and guarantee of act integrity.

eIDAS Regulation No. 910/2014 of the European Parliament: this regulation of direct application in French law defines three levels of signature (simple, advanced, qualified) and requires mutual recognition of qualified electronic signatures within the European Union. In 2024, the eIDAS 2.0 revision (EU Regulation 2024/1183) strengthened digital identity requirements with the introduction of the European Digital Identity Wallet (EUDI Wallet), whose deployment in France is planned for 2026.

Decree No. 2005-973 of August 10, 2005: relating to the electronic authentic act, it lays the groundwork for notarial qualified signature and the REAL infrastructure. Supplemented by CSN orders governing security conditions and signature creation devices used by notaries.

ELAN law of November 23, 2018 (article 20) and Decree No. 2020-395 of April 3, 2020: legalize remote appearance before a notary, govern the conditions of notarial videoconference, and clarify notarial obligations regarding remote identity verification.

Article L. 271-1 of the Building and Housing Code: governs the 10-day withdrawal period of non-professional buyers and the methods of notification (applicable electronically under conditions of traceability).

ETSI EN 319 132 Standard: European standard defining technical requirements for advanced electronic signatures (XAdES) used in professional and institutional exchanges.

GDPR No. 2016/679: the collection of biometric data (facial recognition) in the context of identity verification for electronic signature constitutes processing of sensitive personal data (article 9 GDPR). The data controller must have explicit legal basis and conduct prior impact analysis (DPIA). Electronic signature service providers must guarantee GDPR compliance of their identity verification processing.

Legal Risks in Case of Non-Compliance

Using non-compliant electronic signature on a purchase agreement exposes to several risks: nullity of the preliminary contract for formal defect in case of dispute, inability to enforce proof of signature before civil courts, professional liability of the real estate agent or notary for breach of advisory obligation, and loss of deposit guarantees or immobilization indemnities if the purchase agreement is contested. It is imperative to ensure that the chosen platform provides a proof report (or "proof file") archived and enforceable against third parties, comprising: unique document identifier, qualified timestamping, cryptographic fingerprint (SHA-256 hash or higher), journal of actions by each signatory.

Usage Scenarios: Electronic Signature of Purchase Agreements in Practice

Scenario 1 — An Independent Real Estate Agency Processing 150 to 200 Purchase Agreements Annually

An intermediate-sized real estate agency, with 5 to 8 negotiators, previously managed all its purchase agreements in paper format. Each file required on average 45 minutes of administrative work (printing, initialing, sending registered mail, filing), often supplemented by follow-ups to obtain signed documents from buyers and sellers not residing locally.

After deploying an advanced electronic signature solution compliant with eIDAS, the agency noted a reduction in the average time to collect signatures from 8 days to less than 48 hours. The rate of incomplete files returned (forgotten initial, missing page) dropped from 22% to less than 2%. The logistics cost per file (paper, registered shipments, archiving) decreased by 70%. The agency also valued this modernization as a commercial argument with a clientele of first-time buyers and active online investors.

Scenario 2 — A Real Estate Developer Managing VEFA on Multiple Simultaneous Programs

A real estate developer developing 3 to 5 housing programs in parallel, representing between 80 and 150 reservations annually, faced a complex geographic coordination problem: local, regional buyers, and investors residing abroad, combined with coordinating notaries at multiple offices.

By deploying a qualified electronic signature solution integrated with its CRM tool via API, the developer was able to centralize management of reservation contracts and electronic authentic acts. The time to finalize VEFA sales deeds was reduced by an average of 30%. Documentary compliance (mandatory technical appendices, descriptive notices) was automated via pre-configured templates. The developer was also able to reduce travel costs related to signatures by 45% over one fiscal year, relying on remote notarial signing for expatriate clients. Our AI contract generator can also facilitate drafting of standard documents in this context.

Scenario 3 — A Network of Independent Real Estate Agents Without Physical Agency

A network of independent agents operating exclusively digitally, without a physical agency, needed a fully mobile signature solution, accessible from smartphone or tablet, to finalize preliminary contracts directly during viewings or remotely.

By adopting a mobile-first SaaS platform with integrated identity verification via NFC (reading the chip of an ID card or biometric passport) and advanced signature via OTP SMS, the network reduced its abandonment rate between accepted offer and signed purchase agreement from 18% to less than 5%. The speed of processing and fluidity of the customer journey improved the recommendation rate (NPS) by +22 points over 12 months. Agents also benefited from access to standardized contract templates and legally up-to-date, reducing risks of non-compliant drafting.

Conclusion

The electronic signature of the real estate purchase agreement is today a legally sound reality, provided that appropriate signature levels are respected for the type of act: advanced signature for private deed preliminary contracts, qualified signature for notarial authentic acts. The eIDAS regulation and articles 1366-1367 of the French Civil Code provide a robust framework, strengthened by the rise of remote notarial signing and compliant SaaS platforms.

Choosing the right solution is decisive: user experience, regulatory compliance, probative archiving, and industry integrations are the differentiating criteria. Certyneo offers an electronic signature solution specifically adapted to the challenges of real estate, compliant with eIDAS, certified, and equipped with expert support.

Ready to digitalize your purchase agreements with full security? Start your free trial on Certyneo or contact our team for personalized guidance.