Supported document type
Detect tampered and deepfake Avis d'imposition (French Tax Notice)
An avis d'imposition is the French tax notice the DGFiP issues each year summarising a household's declared income and the tax assessed on it, and it is France's standard income proof for visas, housing files, and means-tested services. It arrives from impots.gouv.fr carrying the revenu fiscal de référence and a 2D-Doc barcode that binds the figures to the tax authority, so undecodable or absent stamps on a digital notice are the loudest tell.
API slug: avis_dimposition
What a genuine avis d'imposition contains
The notice names each member of the foyer, prints the declared income, the revenu fiscal de référence, and the tax assessed, keyed to the année des revenus and the year of issue, which always run one apart: income earned in 2024 appears on a notice issued in 2025. The numéro fiscal identifies the household's account.
Digital notices from impots.gouv.fr carry a 2D-Doc or QR verification stamp whose payload encodes the key figures, so decoding the stamp and comparing it against the printed numbers is the strongest available check. Postal notices arrive without the stamp, which makes reconciliation with payslips and bank records the fallback for those.
How avis d'imposition forgeries are made
Barcode stamp decode
The 2D-Doc payload encodes the notice's key figures under the tax authority's stamp. A stamp that will not decode, or whose payload disagrees with the printed income figures, marks an edited or fabricated notice.
Year-label arithmetic
The année des revenus and the year of issue run one apart, and the notice's figures belong to the earlier year. Labels that match each other, or figures attached to the wrong year, indicate retyping.
Household coherence
Names, parts of the household, and the revenu fiscal de référence must cohere with the payslips and bank records of the same people. Incomes that float above the employment evidence around them are the inflation pattern.
Figure-level print forensics
Edited amounts show up as font-pass changes and realigned digits inside the income table, since figures are usually the only region a forger touches.
What TamperCheck checks on an avis d'imposition
TamperCheck runs 200+ forensic checks across three layers and returns a risk score from 0 to 100 with plain-English findings tied to specific regions of the document. These three carry the most weight on this document class.
Table structure integrity
Inserted and deleted rows leave structural artifacts behind: inconsistent spacing, misaligned columns, and formatting the visible table no longer accounts for.
Stamp authenticity and placement
Stamps are assessed for whether the ink was impressed onto the page or printed as part of it, and for whether the impression was placed digitally after the fact.
Letterhead, logo, and issuer plausibility
Issuer branding is checked for resolution and compression consistency against the body text it sits on. A logo lifted from a website carries the signature of its source, not of the document.
And many more checks
The three above are the layers that carry the most weight on an avis d'imposition. Every upload runs the full suite of 200+ checks regardless of document class, spanning file structure and metadata, pixel-level forensics, font and text rendering, optical and print characteristics, provenance signals, AI-generation signatures, and many more checks.
Who verifies an avis d'imposition, and why
Consulates processing French visa files, landlords, banks, and CAF. In each case the document is being used to unlock money, access, or a legal status, which is exactly what makes it worth forging.
How to verify an avis d'imposition in 4 steps
Collect the notice
Get the full PDF or scan, both pages, keeping the barcode stamp and the income table undistorted.
Decode the stamp
Where a 2D-Doc or QR stamp is present, decode it and compare its payload against the printed figures.
Check years and household
Confirm the revenue year and issue year run one apart, and weigh the household's figures against the payslips and bank records in the file.
Run a forensic check on the file
The stamp binds the figures when it decodes, and the print betrays them when it does not. TamperCheck runs 200+ forensic checks including stamp decode and figure-level analysis, returning a risk score from 0 to 100 with findings tied to specific regions of the image.
Frequently asked questions
What is the revenu fiscal de référence?
It is the household's reference fiscal income, the figure French administrations use for means testing, and it appears prominently on every avis d'imposition. Because housing files and visa files key off it, it is the single most edited number on the document.
Why does my avis d'imposition show a different year than my income?
French notices are issued the year after the income year, so income earned in 2024 prints on a notice issued in 2025. The offset is the rule, and labels that match each other indicate a retyped notice.
Is a paper avis without the QR stamp fake?
No. Postal notices legitimately lack the 2D-Doc stamp, which digital downloads carry. A digital notice claiming impots.gouv.fr origin without a decodable stamp is the combination worth escalating.
How does TamperCheck verify an avis d'imposition?
TamperCheck decodes the 2D-Doc payload where present and compares it against the printed figures, checks the year-label relationship, and reconciles household coherence with the rest of the file. It returns a risk score from 0 to 100 with findings tied to specific regions.
TamperCheck analyses avis d'imposition (french tax notice) uploads with a hybrid forensic and AI pipeline tuned for this document class. Upload endpoints accept PDF and common image formats; class is inferred automatically. See the API documentation for authentication, async jobs, and webhooks.