Since you ask, this is what France says you need to enter as a US citizen:
The following supporting documents must be presented at the request of the Border Police upon your arrival in France:
A valid passport issued less than 10 years before and valid for at
least 3 months after the envisaged departure date
Proof of accommodation covering the whole duration of the stay (hotel
reservation and/or certificate of staying with a relative validated
in the town hall);
Sufficient financial means. The means of subsistence shall be
assessed according to the duration and purpose of the stay and by
reference to the average prices for accommodation and food in the
Member States;
Your return ticket or the financial means to acquire one at the
envisaged return date;
You must have an insurance certificate covering all medical and
hospital expenses for which you may be liable for the duration of
your stay in France, as well as medical repatriation costs and
expenses in the event of death.
https://france-visas.gouv.fr/en-US/web/france-visas/your-arrival-in-france
Of course, the key wording is documents must be presented at the request of and it is very unlikely that Border Police will want more than your passport.