Being part of the Eurozone, France uses the Euro as its currency.

The euro is broken up in to 100 cents (1, 2, 5, 10, 20, 50 cent coins and 1 and 2 euro coins) and 5, 10, 20, 50, 100, 200, 500 euro notes.

Money can be changed at most post offices. Banks have a large minimum commission, and airports, ferry ports and train stations offer poor exchange rates. It is best to obtain small denomination notes €20 or less. Large notes are not easy to use. Many shops/stores do not accept notes of larger than €50.

Credit cards are widely accepted in shops, restaurants and bars in major towns. However, it is advisable to keep cash with you just in case your credit card isn't taken. In more rural areas, small restaurants and shops usually operate on a cash-only basis. Most bed and breakfasts do not accept credit cards. French self-service petrol pumps tend to take only French credit cards (although some autoroute stations are starting to take foreign cards), although you can use most major credit cards at the station kiosk if it is open.

Banking hours vary from town to town and depend on the location, size of branch, etc.  However, general banking hours are Monday through Friday: 9:00am – 5:30pm; some banks are open on Saturdays and certain evenings and many close for lunch, often from 12:00 until 14:00.

Check with your bank to see if they have associate banks in France, because you can get reasonable exchange rates using a bank ATM.  ATMs can be found all over cities, towns and in some large villages (many small village do not have ATM machines), and are generally marked with a sign of a hand holding a card above them.  This eliminates the need to find a place to change money, and the bother of travellers cheques.  Even if your bank doesn't have an associate bank, ATMs still often give the best exchange rates. Some banks may charge you a fee to withdraw from their ATMs. One of the best options currently for Bank of America, PNB Paribas, Scotiabank, Barclays Woolwich, Deutsche Bank or Westpac clients. No extra service fees or charges for ATM withdrawls. Always be careful at ATM machines and cover the keypad with your hand when typing your secret code. 

Travellers cheques in Euros, although secure, are not universally accepted. You can not exchange them at banks, or most hotels, so you will probably need a trip to a post office to cash them. Amex now have a fee-free cashing arrangement at most post offices but a commission of 3% is not uncommon.