Checking the validity of a French identity card : 5 things to look for

Verifying a person’s identity is necessary in many sectors to prevent fraud and identity theft.

The 1995 version of the French national identity card (CNI) remains the most common and widely used document to prove identity: so how to verify a French identity card online and ensure the presented document is authentic? The answer is in this article!

The first step to verify an identity card when you can access the original document is the overall appearance: it must show no signs of cutting, peeling, modification, or any correction.

Pay close attention especially around and near the photo.

Also check that the “RF” perforations in the middle of the card’s edges are present.

The second step to verify a French identity card online is to check the consistency of the information on the document.

The card number can be found in two different places: on the upper part of the front, and in the second line of the MRZ band.

Both must be identical:

The holder’s initials can be found at the top right of the photo:

The holder’s date of birth can also be found in two distinct places: in the middle of the front of the card, and at the end of the second MRZ line in YYMMDD format:

Similarly for last names and first names, which can be found on the card and in the first and second lines of the MRZ band:

At the end of the first line, you will find 6 digits composed of:

– Before February 2017: the two digits of the issuing department + 1 digit related to the issuing service, followed by the agent’s post number with 3 digits.

– After February 2017: “0” followed by the two digits of the issuing department, followed by the agent’s post number with 3 digits.

In the illustration below, the card is clearly not valid because there is no “0” before the two digits of the issuing department, although the card was issued after February 2017.

The two digits of the department from line 1 can be found just after the card issue date, on the second line (without the “0” if card issued after February 2017).

Finally, the last element present three times on the card: the date of issue, which can be found on the back, in the card number, and in the second MRZ line in YYMM format:

The third step to verify a French identity card online: the font!

Official documents use a specific font that is relatively easy to distinguish (see examples above).

Here is an example of a wrong font:

The lower part of the French identity card consists of two lines that contain the information present on the document, with validation keys that prevent reading errors or falsifications.

1. Document Type: 2 characters, code indicating the type of document, represented by the letters “ID”.
2. Issuing Country: 3 characters, the ISO 3166-1 alpha-3 code of the issuing country.
3. Name(s): holder’s last name(s), completed at the end by the character “<“.
4. Department + internal administration code: 6 characters at the end of the line.

1. Card issue date: 4 characters, year and month of issue in YYMM format.
2. Department: 2 characters, same as the department in line 1.
3. Administrative code: 6 characters, assigned by the management center in chronological order according to place of issue and application date.
4. Check digit: 1 character, check digit for the beginning of line 2.
5. First name(s): first name of the card holder, followed by the second first name separated by two chevrons (“<<“).
6. Date of birth: 4 characters, year and month of birth in YYMM format.
7. Check digit: 1 character, check digit for the date of birth.
8. Gender: 1 character, “M” for male, “F” for female.
9. Check digit: 1 character, overall check digit.

A French identity card includes 5 check digits (or security keys) that allow validating the preceding information.

They help avoid transcription errors or modifications, whether intentional or not.

The algorithm used to create and validate the check digits is common to all identity documents: characters have a weight that is multiplied by a factor depending on their position in the string (7, 3, and 1).

Digits have their value (“0” equals 0, “1” equals 1, etc. up to “9” which equals 9), the chevron “<” also has a value of 0, while the weight of letters starts at 10 for the letter “A”, 11 for “B” up to 35 for “Z”.

Let’s take as an example the check digit of the date of birth of the above specimen.

The string to validate is: “200101”.

To calculate the check digit, we proceed as follows:

– “2” has a value of 2 and is in the first position, so it must be multiplied by 7: 2 * 7 = 14.

– “0” has a value of 0 and is in the second position, so it must be multiplied by 3: 0 * 3 = 0, which is added to the previous 14, making 0 + 14 = 14.

– “0” has a value of 0 and is in the third position, so it must be multiplied by 1: 0 * 1 = 0, which is added to the previous 14, making 0 + 14 = 14.

– 1 * 7 = 7 and 7 + 14 = 21

– 0 * 3 = 0 and 0 + 21 = 21

– 1 * 1 = 1 and 1 + 21 = 22

We obtain a total of 22, from which we extract the modulo 10 (the remainder of the Euclidean division by 10), which means keeping only the last digit, which is “2”.

Our check digit is therefore valid because it is 2 that appears on the document!

An identity document has various elements that allow to validate its authenticity.

This is the final step to verify a French identity card online, and the longest one.

In the case of the 1995 version identity card, there are 6 in total, including 4 visible to the naked eye.

A security thread stamped “République Française” is visible just above the signature on the front of the card. To see it, simply hold the card against the light to make it visible.

A Marianne watermark is used on the front of the card, in the upper part:

A second watermark is used on the back of the card, in the lower part (“RF”):

As before, simply hold the card against the light to see them.

Relatively easy to see and check, two golden “RF” bands are present on the front of the card:

Guilloches are the small irregular waves that can be seen on the card: it’s not the easiest element to check online, but generally they should not present inconsistencies between them.

Special attention should be paid to the guilloches present on the photo.

Some elements are visible only under ultraviolet rays, but this requires specialized equipment (so not suitable for online ID card verification).

A fake card under ultraviolet:

A real card under ultraviolet:

You now have all the keys to verify a French identity card online and ensure it is authentic!

No specialized equipment is needed: a little vigilance and time will allow you to avoid most of the frauds that can be encountered daily!

You can also use our service which will perform the verifications in seconds via our web application: results are available directly in the app and as a PDF report!