The 5 most expensive CSRD mistakes for French companies in 2026
Five mistakes appear in the CSRD reports of French companies every year, and they come at a high price: audit revisions, investor inquiries, and last-minute rewrites. Here is what they are and how to avoid them before your next assurance engagement.
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In 2026, the challenges CSRD faced by French companies stem less from a refusal to comply than from an underestimation of the operational requirements of the regulation.
The CSRD requires a data infrastructure that goes far beyond a simple reporting exercise. By 2026, the gap between companies that understood this early on and those that didn't is evident in audit qualifications, investor inquiries, and unbudgeted remediation costs.
Here are the five most costly mistakes this year.
Mistake 1: Treating double materiality as a checkbox exercise
Your double materiality analysis is the foundation for everything else: every disclosure, every data point, and every IRO stems from it. Yet, many companies have conducted it once, filed it away, and forgotten about it. However, double materiality is not static: your value chain evolves, and so does your risk exposure. An analysis performed once in a spreadsheet, without an audit trail or an update process, will be quickly flagged by your independent assurance provider. The recommended approach is detailed in How to conduct your double materiality analysis according to ESRS.
Mistake 2: Believing that AI will produce a reliable CSRD report
In 2026, generative AI has become a standard tool for non-financial reporting. Many companies use it to speed up the drafting of the narrative sections of their CSRD report based on their existing data.
The quality of AI-generated text depends directly on the data that fuels it. Text produced from unstructured, unverified, or untraced data remains unverifiable, no matter how well-written it is.
An independent assurance provider tracing an AI-generated claim back to its source must be able to retrieve the data, methodology, and decision-making process that informed it.
A response generated from governed data has value for an audit. A response generated from ungoverned data remains plausible text, not evidence.
Error 3: Underestimating the actual requirements of limited assurance
A common assumption is thatlimited assurance is less demanding than a statutory audit. Technically, yes. Operationally, the gap is smaller than expected. Your independent assurance provider does not just read your report: they trace every material data point back to its source and verify the collection methodology, calculation basis, internal controls, and validation chain. The scope of this verification is detailed in CSRD limited assurance: what your independent assurance provider will verify in 2026.
Error 4: Reporting on the wrong scope because the value chain has never been mapped
The CSRD requires disclosures across the entire value chain, not just for direct operations. Scope 3emissions, upstream social conditions, and supplier governance: all of these fall within the scope as soon as an issue is deemed material.
Many French companies, particularly in industry and professional services, built their first CSRD report around what they could easily measure: their own operations, their own workforce, and their own energy consumption. The value chain was mentioned, but never truly mapped.
The result is a report that looks complete but fails to cover the material impacts and risks identified by the double materiality analysis. This gap leads to audit qualifications, investor questions, and sometimes a rewrite the following year.
Mapping your value chain is not a one-week project. It requires identifying key suppliers, assessing the availability of their data, and building a process to collect, verify, and govern it over time. Companies that put off this work are now discovering it under pressure.
Mistake 5: Keeping the CSRD disconnected from financial reporting
The CSRD was designed to align sustainability reporting with financial reporting: the same rigor, the same governance, and the same assurance logic. The ESRS standards were built with this alignment in mind.
However, many French companies still manage their sustainability report as a separate process: a distinct team, a separate timeline, and data that never touches the financial reporting infrastructure. The CFO signs off on the financial statements. The CSR director signs off on the sustainability report. The two processes rarely intersect.
This creates inconsistencies that auditors pick up on. And it deprives the sustainability team of the controls and review processes that finance already has in place.
The companies that best manage their CSRD in 2026 are those that have brought the CFO and the sustainability function together around a shared data infrastructure, early in the process. For CSRD, finance-grade governance applied to ESG data is a necessity, not a luxury.
What these mistakes have in common
These five mistakes share a common cause: treating CSRD as a reporting project rather than a data infrastructure challenge. Reporting is the deliverable. Infrastructure is what makes that deliverable defensible, auditable, and repeatable year after year.
Platforms like Harnest are built for this infrastructure challenge. It centralizes ESG, climate, and risk data, maintains a complete audit trail, supports double materiality analysis, calculates Scope 1 to 3 emissions, and produces reports aligned with major ESG frameworks, including CSRD, GRI, ISSB or the VS (formerly VSME), from a single interface.
French sovereign AI means your data stays on French infrastructure—a critical factor for regulated sectors and any organization where data residency is non-negotiable.
If you are preparing for your next CSRD cycle and any of these five mistakes sound familiar, the best time to fix them is before engaging your independent assurance provider, not after.