Public Works Tender: eIDAS-Compliant Electronic Signature in 2026

The building and public works (BTP) sector represents one of the most active sectors in terms of public procurement: in France, public contracts in construction weigh more than 80 billion euros annually according to data from the Legal Affairs Directorate (DAJ) of the Ministry of Economy. Yet complete digitalization of these procedures remains an ongoing project for many companies in the sector. Since October 1, 2018, public contracts exceeding 25,000 € HT must be submitted and processed via electronic platforms. By 2026, regulatory maturity requires enhanced compliance, particularly around qualified electronic signature. This article guides you through the legal obligations, best practices, and concrete solutions to secure your public works contracts through electronic signature.

Why digitalization is essential in public works tenders

The regulatory framework driving digitalization

The Public Procurement Code (CCP), which entered into force on April 1, 2019, consolidated all texts relating to public contracts and concession contracts. It incorporates digitalization requirements from European directives 2014/24/UE (public contracts) and 2014/25/UE (special sectors). Concretely, since 2018 for public buyers and bidding companies, the entire documentary chain — filing of applications, transmission of technical and administrative documents, signing of commitment acts — must be conducted electronically.

Buyer profiles (platforms such as PLACE, AWS-Achat, Maximilien or e-Bourgogne) centralize these flows. Article R. 2132-7 of the CCP explicitly specifies that "consultation documents are made available to economic operators on the buyer profile". Electronic signature occurs at several stages: signing of the commitment act by the successful bidder, signing of amending acts (amendments), but also signing of acceptance records and work situation statements in certain contractual configurations.

Specific challenges in the construction sector

The construction sector presents particularities that complicate digitalization:

• Volume and diversity of stakeholders: a works contract may involve a public client, a project manager, one or more general contractors, declared subcontractors and co-contractors within a temporary grouping of companies (GME).
• Multiple and technical documents: CCTP, CCAP, DC1, DC2, DC4, tax and social certificates, first-demand bank guarantees (GAPD), execution plans… Each document may require signature or electronic approval.
• Tight timelines: open call for proposals procedures impose minimum timelines for receipt of bids (25 days in standard procedure, reducible under certain conditions). Any delay due to signature malfunctions may result in bid rejection.

To understand the fundamentals before addressing the sector-specific regulatory component, the comprehensive guide to electronic signature establishes the essential terminological and legal foundations.

Levels of electronic signature applicable to public contracts

Simple, advanced, or qualified signature: what requirement for construction?

The eIDAS regulation (No. 910/2014) distinguishes three levels of electronic signature, and French regulations on public contracts do not treat them uniformly. The Order of April 12, 2018 concerning electronic signature in public contracts establishes the applicable technical framework in France.

According to this order:

• Advanced electronic signature based on a qualified certificate constitutes the minimum level required for signing the commitment act.
• Qualified electronic signature within the meaning of eIDAS (created using a qualified signature creation device and based on a qualified certificate) offers the presumption of maximum reliability and is recommended for complex contracts or significant amending acts.

It is crucial to understand that simple electronic signature (a simple click or checked box) is insufficient for contractual documents in public contracts. Certification service providers issuing qualified certificates in France are listed on the national trust list (LOTL) published by ANSSI and accessible on the official European Union portal.

To learn more about the distinctions between these levels, the guide on eIDAS 2.0 regulation details the changes introduced by the new regulation and their implications for French companies.

Electronic certificates and their compliance

The qualified certificate must be issued by a qualified trust service provider (PSCQ) listed on the European trust list. In practice, for the construction sector, this means:

1. Obtaining a personal or professional certificate from a PSCQ (ChamberSign, Certigna, DocuSign France, etc.).
2. Verifying compatibility of the signature format with buyer profiles: XAdES, CAdES and PAdES formats are most common, in compliance with ETSI EN 319 132 (XAdES) and EN 319 122 (CAdES) standards.
3. Configuring the workstation with necessary drivers and middleware, particularly for keys on hardware cryptographic media (USB token or smart card).

One often overlooked point: the validity period of the certificate. To ensure the evidentiary value of signed documents beyond certificate expiration, qualified electronic timestamp is essential. It makes it possible to attest that the signature was affixed at a specific moment when the certificate was valid.

Digitalization of construction tender calls: process and best practices

Structuring the documentary flow for bidders

For a construction company bidding on a public contract, digitalization requires reviewing its internal organization. Here are the key steps in an optimized process:

Phase 1 — Monitoring and downloading the call for proposals documentation: The Tender Documents are now fully downloadable from the buyer profile. This step generally does not require signature but may require registration (account creation) on the platform.

Phase 2 — Preparing application documents: Forms DC1 (application letter) and DC2 (bidder declaration) must be completed electronically. Tax certificates (tax compliance, URSSAF certificate) are now issued directly online. Electronic signature for companies covers common business use cases, including administrative acts.

Phase 3 — Signing the commitment act: This is the critical step. The commitment act (AE) or its equivalent in the DUME form (Single Procurement Document) must be electronically signed by the legal representative of the company or their delegate. In the case of a grouping, each member of the grouping signs the DC1 and the mandatary signs the AE.

Phase 4 — Bid submission: Submission occurs before the date and time limits stated in the specifications. An electronically timestamped receipt acknowledgment constitutes proof of timely submission.

Pitfalls to avoid during digitalization

The experience of public buyers and construction companies reveals several recurring errors:

• Confusion between mandatary signature and individual signature: In a joint or solidary grouping, only the mandatary signs the commitment act. Co-contractors sign only documents directly concerning them (DC1 for each).
• Unaccepted signature format: Some buyer profiles do not accept all formats. It is imperative to check the technical specifications of the call before proceeding with signature.
• Expired or revoked certificate: Prior verification of certificate status via the OCSP mechanism (Online Certificate Status Protocol) prevents signature rejection.
• Absence of buyer counter-signature: For the contract to be legally formed, the public buyer must also electronically sign the contract and notify the winning bidder. The notification period triggers the start of contractual obligations.

For companies wishing to evaluate their return on investment before migrating to a dedicated electronic signature solution, the Certyneo ROI calculator makes it possible to quantify expected gains based on document processing volume.

Integration of an electronic signature solution in the construction workflow

Selection criteria for a compliant platform

Faced with the plurality of available solutions on the market, clients and winning companies must select a platform meeting specific criteria for the public contract context:

1. eIDAS compliance: Native support for advanced and qualified signatures, integration with trust service providers listed on the European trust list.
2. Standard signature formats: Support for PAdES for PDFs (most common format in public contracts), XAdES for XML documents, and CAdES for binary files.
3. Traceability and audit trail: Detailed audit log, qualified timestamp, archiving compliant with NF Z 42-013 standard.
4. Interoperability: Ability to interface with buyer profiles via APIs or standardized exchange protocols.
5. Multi-signer management: Essential for company groupings or contracts involving multiple levels of internal validation.

The comparison of electronic signature solutions provides a comparative analysis grid of the main platforms available in France, with their respective strengths for the B2B and public contract context.

Subcontracting and electronic signature: a chain to secure

Law No. 75-1334 of December 31, 1975 on subcontracting requires prior declaration of subcontractors and approval of their payment terms by the client. In a digitalized context, transmission of the electronically signed DC4 (subcontracting declaration) fits into this legal framework.

Electronic signature also secures:

• Monthly work situation statements and their transmission for approval to the project manager then payment by the client.
• Acceptance records (with or without reservations), fundamental acts triggering the start of legal warranties (final completion, two-year and ten-year guarantees).
• Amending acts during execution, which must comply with thresholds for substantial modification defined in article R. 2194-1 of the CCP.

Companies already equipped with an existing solution and wishing to benefit from better integration may consult the Certyneo migration offer for a seamless transition in documentary continuity.

Applicable legal framework for digitalized public works contracts

The digitalization of public works contracts is part of a dense legal corpus, articulating national and European law. Here are the fundamental texts that every company in the sector must master.

Public Procurement Code (CCP) — Entered into force on April 1, 2019, it codifies ordinances No. 2015-899 and No. 2016-65. Articles R. 2132-1 to R. 2132-14 govern the modalities of making consultation documents available and electronic submission of bids. Article R. 2182-3 requires electronic signature of the commitment act for formalized contracts.

Order of April 12, 2018 — Issued in application of decree No. 2016-360, it specifies the conditions for using electronic signature in public contracts. It requires the use of a qualified certificate within the meaning of eIDAS regulation and signature formats compliant with ETSI standards.

eIDAS Regulation No. 910/2014 — This European regulation, directly applicable in French law, establishes the legal framework for electronic signatures, electronic seals, electronic timestamps and authentication services. Qualified electronic signature benefits from a presumption of reliability equivalent to handwritten signature (article 25, paragraph 2). eIDAS 2.0 regulation (EU regulation 2024/1183), in the process of deployment, will strengthen interoperability requirements via the European digital identity wallet (EUDIW).

Civil Code, articles 1366 and 1367 — Article 1366 establishes the principle of equivalence between electronic and paper writing, provided the author is identified and integrity is guaranteed. Article 1367 defines reliable electronic signature as that "which consists of the use of a reliable identification method guaranteeing its link with the act to which it is attached".

ETSI Standards — ETSI EN 319 132 (XAdES), EN 319 122 (CAdES) and EN 319 102 (PAdES) standards define the technical profiles of advanced and qualified electronic signatures. They are made mandatory by the 2018 order for public contracts.

GDPR No. 2016/679 — Digitalization involves the processing of personal data (identity of signers, electronic certificates). Public buyers and platform operators have the status of data controller or processor depending on configurations. Obligations regarding retention period, right of access and data minimization apply fully.

NIS 2 Directive (2022/2555/UE) — Transposed into French law by law No. 2023-703 of August 1, 2023, it imposes enhanced cybersecurity requirements on essential and important entities, categories that may include operators of public procurement platforms and certain major construction clients. Security incidents affecting signature systems must be reported to ANSSI.

Legal risks in case of non-compliance: A signature affixed with a non-qualified certificate or in a non-compliant format may result in bid irregularity and rejection. During execution, a commitment act or amendment signed without respecting regulatory requirements exposes the company to a challenge to the evidentiary value of the document, or even nullity of the act under articles 1366 and 1367 of the Civil Code.

Use cases: electronic signature in action in construction

Scenario 1 — An SME in construction managing 40 calls for proposals per year

An SME specializing in secondary works (approximately 80 employees, specialized in aluminum carpentry and glazing) was responding through 2024 to about forty public calls for proposals per year by combining paper processes and scanned document submissions. The manager and commercial director had to affix their handwritten signatures to the commitment act, digitize documents and submit them to buyer profiles, with a frequent risk of format errors or deadline overruns.

After deploying a qualified electronic signature solution integrated with their commercial management software, the time for preparing and signing administrative documents decreased from 4 hours to less than 45 minutes. Systematic traceability (qualified timestamp, audit log) reduced disputes related to proof of timely submission by 90%. The rate of bids rejected for formal defects dropped to zero over the 18 months following deployment.

Scenario 2 — A temporary grouping of companies (GME) for a thermal renovation contract

Three companies — a thermal engineering firm, an external insulation specialist and a tertiary electrician — group together as a joint GME to bid on a thermal renovation contract for a social housing complex estimated at 3.2 million euros HT. The procedure is an open call for proposals subject to the CCP with complete digitalization.

The complexity lay in the need to collect DC1 signatures from each of the three members, located in different cities, then the signature of the commitment act by the designated mandatary. Thanks to an electronic signature platform managing multi-signer workflows with sequencing, the validation circuit was completed in less than 3 working hours, versus 2 to 3 days with previous paper or email exchanges. The entire portfolio of 47 documents was signed and submitted 72 hours before closing, eliminating any timeline risk.

Scenario 3 — A public client managing notification and execution of works contracts

A territorial authority managing a multi-year investment program (approximately twenty concurrent works contracts, with an annual volume of about 15 million euros) undertook to digitalize the entire contractual chain, from notification to acceptance records.

Before complete digitalization, signing amendments required physical back-and-forths between the technical department, legal department, the elected signing official and the company. The average processing time for an amendment was 18 working days. After deploying a solution incorporating qualified electronic signature and digital signature delegation, this deadline fell to 4 working days, a reduction of 78%. Automatic archiving of signed documents in the authority's document management information system also secured evidence preservation for potential regional accounting office audits.

Conclusion

Digitalization of public works contracts is no longer an option: it is a structuring regulatory obligation, governed by the Public Procurement Code, eIDAS regulation and the 2018 order. By 2026, construction companies that have not yet adopted a qualified electronic signature solution face real risks: bids rejected for formal defects, missed deadlines, disputes over the evidentiary value of contractual acts.

The good news: robust, compliant and easy-to-deploy solutions exist, including for SMEs. They make it possible to secure each stage — from bidding to project completion — while significantly reducing administrative timelines and processing costs.

Certyneo supports you in this transition with an eIDAS-compliant platform, adapted to the multi-signer workflows specific to construction. Start your free trial or request a demo to discover how to effectively digitalize your public contracts.