Hi @CamilleB,
Could you please share a screenshot of your flow's configuration?
Do you want to store a file in a SharePoint list as a attachment of an item?
Do you want to copy (not create) a file which was approved from an item of first list into an item of second list?
Or want to copy a file from a SharePoint library to another SharePoitn library?
If you want to copy (not create) a file which was approved from an item of first list into an item of second list, I afraid that there is no way to achieve your needs in Microsoft Flow currently.
If you provide more details about your scenario, I would provide a proper solution for you.
Best regards,
Kris