How to write a strong CIR technical file
Introduction
As the Research Tax Credit filing deadline approaches, many companies focus on the amounts to be declared, R&D salaries, depreciation or approved subcontractors. These elements matter, but they are not enough. The real foundation for securing a CIR claim is the CIR technical file
The CIR technical file demonstrates that the activities being claimed genuinely qualify as research and development from both a tax and scientific perspective. It is not simply a matter of describing an innovative project or presenting an ambitious product. You need to demonstrate that your company encountered scientific or technical uncertainties, followed a structured experimental approach, and produced new knowledge or know-how through its work.
A poorly prepared file can weaken your claim, even if the financial calculations are correct. Conversely, a clear, well-documented and well-supported CIR technical file significantly reduces the risk of your claim being challenged in the event of an audit.
The authorities’ expectations are detailed in the official resources published by the French Ministry of Higher Education and Research, including the 2025 CIR Guide and the official template for the supporting file covering R&D activities declared under the CIR. The supporting documentation requested during an audit includes, in particular, a scientific and technical description of the work carried out and a financial table.
Why the CIR technical file is essential
The Research Tax Credit is a powerful tax incentive that enables companies to finance part of their research and development activities. The French Ministry of Higher Education and Research defines the CIR as a tax incentive designed to encourage companies to increase their scientific and technical research efforts.
However, claiming that a project is innovative is not enough to qualify for CIR. A company must be able to demonstrate that the activities declared constitute genuine R&D operations.
That is precisely the purpose of the CIR technical file. It explains the scientific context, objectives, state of the art, uncertainties encountered, experimental approach and contributions generated by the project.
In the event of an audit, the authorities may request supporting documentation. The French Ministry for the Economy states that companies must provide the documents required to assess the eligibility of the expenditure claimed, including technical documentation demonstrating that the activities qualify.
Present your company and R&D strategy
A strong CIR technical file begins with a clear presentation of your company. This first section should provide an overall view of your business: sector, history, positioning, key achievements, internal organisation and the role R&D plays in your development.
The objective is not to produce a marketing brochure. It is to provide context for the activities being claimed and demonstrate that R&D is not an isolated activity, but a structured part of your business.
You can outline your R&D strategy, research areas, technological objectives and relevant indicators. For example, you may include scientific publications, patents filed, PhD research supervised, collaborations with laboratories, technology partnerships or projects carried out with research organisations.
This section helps the authorities understand who you are, why you conduct R&D and how these activities fit into your broader development strategy.
Define the project’s scientific and technical objectives
Each project being claimed must then be presented individually. The first step is to define its scientific and technical objectives clearly.
This section should answer one simple question: what is your company trying to demonstrate, solve or overcome?
A CIR objective should not be expressed solely in terms of product development, market goals or commercial performance. Statements such as “we want to launch a new platform” or “we want to improve the user experience” are not sufficient. The objectives must be framed in terms of scientific knowledge or technical challenges.
For example, you should explain how the project contributes to advancing knowledge in your field, or how it seeks to solve a non-trivial technical problem.
This distinction is important: CIR supports R&D, not standard product development.
Establish the state of the art without confusing it with the state of the market
The state of the art is one of the most important sections of a CIR technical file. It is also one of the most frequently misunderstood.
Many companies confuse the state of the art with a market analysis. They are not the same thing.
A market analysis describes existing solutions, competitors, user behaviours and commercial trends. The state of the art analyses the scientific and technical knowledge available in a given field.
To prepare this section, you should draw on bibliographic references such as scientific papers, technical publications, standards, patents, research reports and specialist documentation. The aim is to demonstrate that the knowledge available at the time of the project did not provide a direct solution to the problem you encountered.
The state of the art should therefore highlight the limitations of existing knowledge. These limitations form the basis for demonstrating the existence of scientific or technical uncertainties.
A well-constructed state of the art shows that your project is not simply applying a known solution, but exploring an area of genuine uncertainty.
Describe the technological barriers and scientific uncertainties
Once the state of the art has been established, you need to describe the technological barriers and uncertainties encountered.
A technological barrier essentially answers the following question: why would what you are trying to achieve be difficult for a competent professional in the field?
It is not enough to say that the project was difficult, lengthy or expensive. You need to demonstrate that the challenge went beyond standard professional knowledge and could not be resolved simply by applying existing solutions.
These barriers are closely linked to the state of the art. Once you have clearly identified the limitations of existing knowledge, you can explain why your team needed to experiment, test, compare, fail, adjust and develop a new response.
A strong CIR technical file describes the initial uncertainties precisely and then explains how the R&D process addressed them.
Present the experimental approach
The experimental approach is at the heart of the CIR technical file. It demonstrates that your company genuinely carried out research and development activities.
You should present the stages of your R&D process methodically: hypotheses formulated, methods used, tests conducted, protocols followed, results obtained or expected, adjustments made and successive iterations.
Where possible, this section should be supported with evidence such as diagrams, prototype photographs, results tables, graphs, screenshots of tools, extracts from internal reports or technical schematics.
The objective is to make the process verifiable. The authorities should be able to follow the scientific or technical reasoning: problem identified, hypothesis formulated, experiment conducted, result analysed, conclusion reached.
The clearer this logic is, the stronger your file will be.
Describe the scientific and technical contributions
Once the work has been detailed, you need to step back and explain its broader contribution.
The section on scientific and technical contributions should explain what your company has genuinely added to the field.
This may include new knowledge, new know-how, original methods, technical architectures, improved processes or new avenues opened up by the work carried out.
This section is essential because it demonstrates that the project did more than produce an internal deliverable. It shows that the work advanced the understanding or technical mastery of a particular problem.
Even if the results were not entirely successful, they may still have R&D value. A documented failure can demonstrate genuine scientific exploration, provided that it is analysed and properly justified.
Present the human resources involved
The CIR technical file must also describe the people involved in the project.
Job titles alone are not sufficient. You need to explain each employee’s actual role in the research project.
For each person involved, it is useful to specify their education, expertise, responsibilities within the project, technical contribution and how their time was allocated to R&D activities.
This section must be consistent with the personnel costs included in the CIR eligible expenditure base. If an employee’s cost is being claimed, their scientific or technical involvement must be clearly documented.
The French Ministry of Higher Education and Research specifies that the supporting file must include a scientific and technical description written in French by the R&D personnel who contributed to the activities being claimed.
Align the technical file with the financial claim
A CIR technical file should never be disconnected from the financial section of the claim.
The projects described must correspond to the expenditure being claimed: salaries, depreciation, subcontracting, operating costs and other eligible expenditure.
If the technical and financial sections tell two different stories, the risk of additional information requests or a challenge to the claim increases.
Common mistakes to avoid
The most common mistakes in CIR technical files tend to be the same. The file may be too commercial, too vague or too focused on the product. It may lack a proper state of the art, confuse innovation with R&D, or fail to demonstrate the technical uncertainties involved.
Another common mistake is failing to connect the activities described with the people involved and the expenditure being claimed.
A strong file must be clear, consistent and traceable. It should use the language of R&D, not marketing.
How Flag supports you with your CIR technical file
At Flag, we help you build a robust, clear and defensible CIR technical file.
We support you with project qualification, defining scientific objectives, preparing the state of the art, describing technological barriers, structuring the experimental approach and ensuring consistency with the financial claim.
Our objective is simple: secure your CIR claim, reduce the risk of a tax reassessment and allow you to stay focused on growing your business.
Explore our services.
Contact us here.
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Conclusion
Preparing a strong CIR technical file requires structure, rigour and anticipation.
A robust file begins with a clear presentation of the company and its R&D strategy. It must then demonstrate the scientific objectives, state of the art, technical barriers, experimental approach, contributions generated and the role of the teams involved.
As filing deadlines approach, improvisation is best avoided. A well-structured technical file is one of the most effective ways to demonstrate to the authorities that your project qualifies for CIR and to reduce the risk of a tax reassessment.
Want to secure your CIR technical file? Let’s talk.
Not sure where to start? Reach out, we’ll walk you through it.
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