What is the smartest and cheapest way to turn dollars into Euros
before we travel to France next week?

I guess smartest way is to use Visa or Master card to pay everything
you want in France. In this case the exchange rate is normal and 0% of
extra payments. If you want cash (from personal experience) the most
easy and perhaps cheapest way is to withdraw them at a bank withdrawal
automate in France.

Forgotten to say that at least visa charges 2euro per transaction +
2-2,5% of transaction amount if you withdraw money from an automate.
this is at least valid for europe.

Go to your bank

I agree with Tolick.  You can buy Euro notes at a bank, of course, but
there will also be ATMs at the French airport.  Don't depend on just
one card; sometimes the systems can't connect, will even tell you your
card has expired.  Hotels may also block an amount to cover the room
and expected incidentals, which could tie up use of a card.

Yes, there are charges for using ATMs, so you shouldn't draw too small
amounts.  Don't keep all your cash in one place and not with your
plastic cards and ID.

Personally, I think it is a waste of time to worry about finding a
cheaper exchange rate or service.  In France, it probably cannot be
done, and any possible saving is not worth the effort and time.

Have a great trip!

I think it is smarter to use your credit/debit cards for paying.But
you can't use your cards at small shops.so, you should change some of
your dollars into euros for your use.The credit or debit card of yours
are the cheapest way that can change your money.