This matches the Schengen and ICAO biometric size.
Questions
What size is a France passport and ID card photo?
35 x 45 mm. At 300 DPI that is 413 by 531 pixels, which is the size this tool exports.
How big should the head be in a France passport and ID card photo?
Between 32 and 36 mm measured from the chin to the top of the head. The tool crops to the middle of that range and tells you the measurement it reached.
Is my photo uploaded anywhere?
No. The face detection and the cropping both run in your browser using WebAssembly. The image data stays in the tab and is gone when you close it. There is no server to upload it to.
Can I use a phone selfie?
Yes, and that is what most people do. Face the camera straight on with a plain wall behind you and even light on your face. Hold the phone at eye level rather than above you.
What background does France want?
Plain light grey. If your wall is close enough, keep the original. If not, the tool can replace the background on your device, which takes a few seconds the first time.
Will my photo definitely be accepted?
Nobody can promise that, and this tool does not. It gets the dimensions, head height and resolution to the published requirements. Whether your expression, clothing and lighting pass is decided by the office you apply to.
Can I print it?
Yes. Along with the single photo you get a 4 by 6 inch sheet with several copies tiled on it and cut lines between them. Any shop that prints 4 by 6 photos will print it.