Will my tax return be checked if I complete it using the MyGuichet assistant?

Not initially. The MyGuichet assistant is an online data entry tool: it allows you to fill in the fields of your tax return yourself and submit it to the ACD electronically. However, it does not carry out any manual checks beyond verifying the technical consistency of the fields you have filled in (date formats, numerical amounts, mandatory fields, etc.).

At the provisional assessment stage, your tax return is not examined by an ACD officer. No checks are carried out on the deductions to which you may be entitled: travel expenses, mortgage interest, insurance, pension contributions, extraordinary expenses, acquisition costs, donations to approved organisations, etc.

This means that:

• A missed box is not flagged by the wizard.
• A misunderstood section is not corrected.
• A deduction to which you were entitled but which you did not enter is not added.

The provisional statement reflects exactly what was entered in the MyGuichet assistant, no more and no less. If your tax return contains an error or an omission, this is directly reflected in the tax calculation, and the provisional statement you receive reflects this.

The actual verification of your return takes place later, when the final statement is issued. At that point, an official from the tax office will examine your file and supporting documents, but this process can take up to 5 years.

Updated on: 26/05/2026