Taxation and declarations: VAT, IS, advance payments

Updated March 2026 - Many tax errors come not from bad calculation, but from bad timing. VAT, IS deposit, IS balance, tax package, CA12 or specific obligations: each flow has its own logic. In 2026, good management consists of organizing these deadlines in a single system.

Depending on your diet, you may have:

• ▸a monthly or quarterly CA3;
• ▸a CA12 or CA12 E with the simplified regime;
• ▸declarations linked to specific flows, such as imports or certain additional taxes.

The DGFiP calendar reminds for example that in normal real regime, monthly deposits take place between the 15th and the 26th depending on the date appearing in the professional space.

The classic trap is to put everything under the corporate tax label. In reality, we must distinguish:

• ▸IS deposits;
• ▸the IS balance;
• ▸the 2065 results declaration and its annexes.

The 2026 calendar notably mentions, for companies closing on December 31, 2025 or January 31, 2026, a deadline for electronic payment of the IS balance of May 15, 2026. The tax package follows its own calendar logic.

For financial years ending on December 31, 2025, the practical date for submitting the package by teleprocedure is generally May 20, 2026, taking into account the additional time allowed for teletransmissions.

You can complete with Tax package submission deadline 2026, our article on the VAT declaration and our VAT reverse charge guide.

Hayot Expertise Advice: A good tax calendar does not just list dates. It links each deadline to the documents to be produced, the internal manager and the expected level of control.

We recommend management in three layers:

1. ▸monthly recurring obligations;
2. ▸closing obligations;
3. ▸exceptional or sectoral obligations.

We build with our clients an operational tax calendar linking VAT, IS, advance payments, bundles and control points.

👉 Putting your tax calendar under control

Tax compliance 2026 is as much about the method as it is about the rules. When deadlines are clearly mapped, taxation once again becomes a subject that is managed, not imposed.

📞 Do you want to secure your VAT and IS calendar? We can put in place a clear timetable and review of key deadlines. Make an appointment with Hayot Expertise

(Official sources: impots.gouv.fr - professional tax calendar 2026, impots.gouv.fr - declaration and payment of VAT, impots.gouv.fr - telepayment of IS)