Is a visa number suitable for opening a bank account?
The numéro d’identification fiscale is your tax office identification number
I am on my first-year visa which serves as my residency card. I do not have my social security number yet. I am opening a bank account and they need my numéro d’identification fiscale and I do not know what to use. Do I insert my visa validation number?
No, your visa number is not relevant to this, nor is your social security number (note that it should be possible to obtain a provisional social security number fairly rapidly). The numéro d’identification fiscale, also called numéro fiscal, is your tax office identification number.
Anyone who has ever paid French tax should have one of these, which you can find on local property tax bills and on pre-filled versions of income declaration forms.
If you have not been concerned with French tax yet, you should contact your local French tax office to obtain a number, with proof of your ID and residency in France, such as passport and recent utility bills.