Key Tax Deadlines for September 2026: What Individuals and Businesses Need to Know

September marks a critical period for tax compliance in France, with several important deadlines for both individuals and businesses. According to the official calendar published by the Direction générale des impôts (DGI), taxpayers must adhere to specific dates for monthly declarations and the payment of the second provisional installment.

Deadlines for Individuals (Natural Persons)

For individual taxpayers, the key dates are as follows:

September 15, 2026: Deadline for submitting the monthly tax declaration.
September 25, 2026: Deadline for submitting the declaration for the second provisional installment.

Deadlines for Businesses (Legal Entities)

Businesses have different deadlines depending on their filing method:

September 21, 2026: Deadline for businesses using the e-filing and remote payment system to submit their monthly tax declaration.
September 28, 2026: Deadline for all other legal entities to submit their monthly tax declaration.
September 28, 2026: Deadline for all legal entities to submit the declaration for the second provisional installment.

Important Recommendations from the DGI

The DGI emphasizes that these dates represent the final day of the legal deadline. To ensure a smooth process, the agency strongly recommends that taxpayers complete their filings before the deadline. This proactive approach helps to:

Avoid overcrowding at tax collection centers.
Prevent potential overloads of the digital tax system.

By planning ahead, taxpayers can avoid last-minute issues and ensure full compliance with their tax obligations.