The Euro:
France belongs to the euro zone. (Its old currency, the franc--or, more accurately, the "new franc"--was retired in 2002.) Please don't embarrass yourself and annoy the locals by trying to pay or tip in dollars, pounds sterling, or another foreign currency.
ATMs nearly always have better rates than currency-exchange offices and hotel reception desks.
About ATMS in Paris:
You'll find ATMs on banks and post offices all over Paris, and most of them have step-by-step instructions in your choice of French, English, and other languages.

Before leaving home, tell your bank that you'll be visiting France. (Some banks--even large ones--disallow foreign transactions for security reasons unless they've been notified ahead of time.)

Be prepared to use a four-digit numberic PIN. If your bank uses a six-digit PIN or a combination of letters and numbers, ask the bank to change your PIN or to provide instructions for using your ATM card overseas.

You'll nearly always pay a small transaction fee on cash withdrawals outside your bank's ATM network. What you may not know is that many banks have foreign-exchange surcharges of up to 5 percent on overseas cash withdrawals. So effectively you are paying the conversion fee as well as your own banks overseas withdrawal fee as well as the ATM's withdrawal fee. If your bank has such a policy, you may want to change banks or use a CASH PASSPORT CARD (Travel Card) where you can lock in exchange rates each time you load and reload the card (transferring from your AU or US bank account to the cash passport card in EURO) 
FOR a MAP LOCATION of ALL ATM's in Paris to see which is closest to you CLICK HERE 

Travel Cards:
Most banks offer prepaid travel cards that work the same way as the Cash Passport card allowing you to lock in rates to help manage your spending while overseas and where you can lock-in the exchange rate for up to 13 currencies.  You will know how much you have to spend, no matter how the Australian dollar moves. 
Using credit Cards:
Visa and MasterCard are accepted by most shops and restaurants, though smaller merchants, some neighborhood restaurants or bars, and street vendors may not take credit cards. (Also, restaurant tips are normally given in cash.)