TLDR
As a general rule, you can fully deduct advertising expenses from the result for the financial year in which they are incurred. However, the available sources specify neither the supporting documents to retain nor a specific form or procedure for declaring this deduction. You must distinguish this deduction from the tax applicable to certain purchases of online advertising services.
General deductibility rule
As a general rule, the BOFiP classifies advertising and propaganda expenses as deductible management expenses. They are fully deducted from the result for the financial year in which they are incurred.
This source sets out a general rule applicable to advertising expenses, without expressly specifying the documentary treatment applicable to online campaigns.
Deduction documentation and procedure
The available sources do not list the invoices, receipts, contracts or other supporting documents to retain in order to deduct an online advertising expense. Nor do they identify any specific form or procedure for declaring this deduction.
You must therefore distinguish the tax deductibility rule, which is documented, from the specific documentary requirements, which are not specified in the sources examined.
Tax on certain online advertising services
The deduction of the expense must not be confused with the tax provided for by Article 302 bis KI on the purchase of certain online advertising services.
This tax applies to the taxable person subject to VAT and established in France. It applies to the amounts paid excluding VAT for the services concerned, and its rate is set at 1%. It is assessed and paid for the previous calendar year when the VAT return for March or the first quarter of the calendar year is filed.
These rules concern the tax on the purchase of online advertising services and do not constitute a specific procedure for deducting the expense.
Limitations to verify
Expenses relating to advertisements prohibited by Articles L. 3323-2, L. 3323-4 and L. 3323-5 of the Public Health Code are not eligible for deduction. The available sources do not make it possible to determine whether an online advertisement concretely falls within these prohibitions.
In a particular case, advertising expenses incurred to create a brand or give it greater reach, when they are disproportionate to annual profits, may be considered initial establishment expenses and be subject to amortization. The BOFiP does not specify separate treatment for online advertising.
Informational content, not personalized tax advice.