Tax site gives option for a rescrit: what is this?

You should submit your request before the declaration deadline

What is a rescrit? I’ve see an option to request one inside my account at impots.gouv.fr?

A rescrit fiscal is a longstanding option available to taxpayers in France which more people may have become aware of this year, since the option to make one online via your personal space was added. This can be found under the Autres services button on the top right.

Traditionally this had to be done by registered post letter with proof of receipt (lettre recommandée avec avis de reception), which is still possible.

This is for situations where you are unsure of your interpretation of an element of French tax law and how a particular rule relates to your situation. It could include, for example, whether or not you are eligible for a certain tax reduction or a certain deduction from taxable income.

In formulating a request, you should, if possible, mention the actual article of tax law concerned (this will often be from the Code général des impôts) or at least provide enough information for the tax office to identify the rule you are asking about. 

You may wish to check the question has not already been answered in recent rescrits published at: bofip.impots.gouv.fr/rescrits.

You should give enough detail about your own situation to allow the tax office to take a position.

With regard to income tax, you should submit your request before the declaration deadline. You should receive a reply within three months but it may be less, and this is definitive.

If you have not had a response by the time you come to declare and you are later found to have made a mistake concerning the issue you asked about, you will not be charged interest if you later have to correct your return.

The rescrit is similar, but not identical, to the mention expresse, which allows you to inform the tax office about an issue you have some doubts about during your declaration.

Note that if you have a straightforward question about tax, unlikely to require in-depth analysis, you can simply ask your question via private messaging.