Patents: INPI costs and protection strategy

Quick answer. In 2026, filing a patent at the INPI costs at least around 636 euros (filing 26 euros, search report 520 euros, grant 90 euros), plus rising renewal fees of 38 to 790 euros, totalling around 4,500 euros over the 20-year protection period. Individuals and SMEs get a 50 percent discount. On the tax side, the costs feed the research tax credit and the patent income may qualify for the IP Box at 10 percent.

A patent is not only a matter for engineers and IP attorneys. It is also an investment decision that weighs on cash flow at launch, sits on the balance sheet for years, and unlocks tax levers that are often overlooked. For a deeptech founder or an industrial SME director, the real question is not only how to protect an invention, but how much it truly costs, how to record it on the balance sheet and how to recover part of it through tax.

We address the three dimensions together: the real cost at the INPI, the protection strategy to calibrate to your business, and the accounting and tax treatment from a chartered accountant's standpoint. The aim is for you to walk into your IP attorney's office already knowing what the patent will cost and what it can return.

The basic procedure at the INPI rests on three main fees. At the standard 2026 rate, the filing fee is 26 euros, the search report fee is 520 euros and the grant fee is 90 euros. The minimum to obtain a granted patent is therefore around 636 euros in official fees.

That figure is only part of the total cost. Once granted, you must pay annual renewal fees to keep the patent in force. These fees rise over time: they start at 38 euros per year for the first years and reach around 790 euros per year for the last ones. Over the full 20-year protection period, the renewal fees total around 4,500 euros.

These figures only cover the fees paid to the INPI. They do not include the fees of an IP attorney for drafting the application, nor any foreign extensions, which can far exceed the French fees.

The INPI applies a 50 percent discount on the main fees for certain applicants. It is available to individuals, to SMEs with fewer than 1,000 employees whose capital is not held 25 percent or more by a non-eligible entity, and to non-profit organisations in the research and education sectors.

This discount is not granted for the whole life of the patent. It is no longer available beyond the 7th annuity. In other words, the relief covers filing, search, grant and the early renewal years, but the highest fees, which fall late in the patent's life, are paid at full rate.

For most of our startup and SME clients, this discount halves the entry ticket. You still have to check the capital-ownership condition: an SME mostly held by a non-eligible group may lose the benefit. We review this point with you before filing, as part of our corporate legal advisory.

A patent protects your invention for 20 years from the filing date. This period is a maximum and is conditional: protection is only maintained if you pay each renewal fee. An unpaid annuity causes the patent to lapse, and the invention then enters the public domain.

This has a strategic consequence. Not every patent deserves to be kept for 20 years. Many companies deliberately let obsolete patents lapse to stop paying the most expensive fees. Managing a patent portfolio is therefore a budgeting exercise, year after year.

A patent is not always the right tool. Before filing, you must test your invention against the reality of your business and your ability to defend your rights. Here is the approach we recommend to protect and budget an invention.

1. Check the patentability of the invention: novelty, inventive step and industrial application are the three substantive conditions. A prior public disclosure can destroy novelty.
2. Secure the earlier date upstream, for example with a Soleau envelope, which provides low-cost proof of date without granting any monopoly.
3. Define the geographic scope: France only, Europe or international. Each extension multiplies costs and imposes deadlines to meet.
4. Weigh patent against secrecy. A process that is hard to reverse-engineer may be better protected by secrecy, which avoids publication and has no time limit, but grants no enforceable monopoly.
5. Budget the whole: INPI fees, attorney fees, renewal fees over the intended period, and where relevant foreign extensions.

This is where a chartered accountant adds value few applicants anticipate. The costs of obtaining and maintaining patents are among the expenses eligible for the research tax credit, set out in article 244 quater B of the French tax code. In practice, part of the fees and costs tied to protecting your inventions can feed your R&D tax credit base, and so reduce your tax.

This eligibility is especially valuable for structures already carrying out research and development and using the R&D tax credit or the innovative new company status. If that is your case, the patent should not be treated in isolation but built into your overall innovation-aid strategy. We coordinate these points within our CIR, CII and JEI support, and you can dig into the mechanics with our article on the reform of the JEI status in 2026.

The patent acquired or filed is also an intangible asset on the balance sheet. It is amortisable over its protection period or expected useful life. The cost is therefore not a charge fully deducted in the year of filing, but a value spread accounting-wise, which changes the look of your result and equity.

The IP Box, set out in article 238 of the French tax code, is a favourable regime too rarely used by SMEs. On option, the net income from the sale, licensing or sub-licensing of patents and assimilated assets is taxed at a reduced corporate income tax rate of 10 percent, instead of the standard 25 percent rate.

The assets covered go beyond patents: utility certificates, software protected by copyright and certain manufacturing processes also qualify. Trademarks, designs and models, however, are excluded from the regime. A startup that licenses a patented technology or a protected piece of software may therefore see part of its income taxed at 10 percent rather than 25 percent.

This reduced rate is not automatic. It applies subject to a so-called nexus ratio, which reflects the share of research and development expenditure carried out in France. The more your R&D is located and tracked in France, the higher the share of income eligible for the reduced rate. This requires rigorous cost accounting, which we set up as part of our chartered accountancy services in Paris 8.

Too many founders look only at the 636-euro entry ticket and then discover the renewal fees, attorney fees and extension costs. A patent is a multi-year commitment, not a one-off purchase. Conversely, many directors do not realise that protection can be partly refinanced through the R&D tax credit, and that patent income may fall under the IP Box at 10 percent. Our conviction is that the decision to patent must be taken looking at both sides: the cost over time and the possible tax return.

A frequent case in our files: a deeptech startup approaches us before filing. The founder has budgeted 636 euros and stops there. We rebuild the full budget with them: fees cut by 50 percent thanks to the eligible SME status, rising renewals over the intended protection horizon, and drafting fees. In parallel, we check that the patent costs feed the R&D tax credit base, and we anticipate how licence income will be treated under the IP Box. The patent stops being an imposed expense and becomes a line in the financing plan, consistent with their preparation of a first fundraising round.

The 50 percent discount depends on precise size and capital-ownership conditions, and it disappears beyond the 7th annuity: do not count on it for the most expensive fees. A missed annuity puts the patent into the public domain, sometimes for good. The IP Box requires fine tracking of research and development expenditure to justify the nexus ratio: without suitable cost accounting, the benefit is fragile in case of an audit. Finally, a patent publishes your invention, which can be a drawback compared with secrecy for some processes.

As a chartered accountant registered with the Ordre and a statutory auditor, we work on the economic and tax side of the patent, alongside your IP attorney for the technical and legal side of the application. If you are launching your structure, our notes on the structuring choices at startup launch and our support for tech startups usefully complete this thinking.

Hayot Expertise advice. Before filing, set a budget over the whole protection period, check your eligibility for the 50 percent discount and connect it to your R&D tax credit. If you plan to license the technology, study the IP Box option from the start, as it is prepared upstream through the quality of your research-expenditure tracking.