Making phone calls to and from France
Making calls to France from the US, or making calls within France during your stay, can seem complicated and confusing, but it's totally easy if you know a few simple rules.
Recognizing French phone numbers
French phone number are ten digits, often written as five pairs of numbers (with a space, period, or dash in between the pairs).
Most fixed/land lines in France start with 01 or 09. Cell phones always start with 06.
So an example of a French cell phone number is 06 55 55 55 55. The 06 means it's a cell phone; get it?
Calling a French phone number from within France
The rules for calling a French phone number can vary a bit depending on where you're calling from. If you're calling a French phone number from a French phone (i.e. from your hotel, or from a cell phone you're using in France), you dial the ten digits exactly as they're written.
Calling a French phone number from the United States
If you're calling a French phone number from the US, it's a little bit trickier. You'll need to add some numbers in the beginning, and also drop the first zero from the ten-digit number.
So, let's use the cell phone example I gave above: 06 55 55 55 55. To call this number from the US, you'd dial 011 33 6 55 55 55 55. A breakdown of those numbers:
011 = This means you're making an international call.
33 = This is France's country code.
6 55 55 55 55 = The phone number, with the first zero removed. Why? I dunno!
So remember, when calling a French number from within France, you keep the first zero of the ten-digit number, and when calling a French number from the US, you can drop it. That first zero is often written in parentheses to imply that you might dial it or not, depending on where you're dialing from. So you might see a French phone number written as (0)6 55 55 55 55. It's easy if you know what to look for.
Calling the US from France
To dial a US number from any French phone (fixed line or cell phone), you'll dial 001 and then the ten-digit American phone number. So to call the US phone number 555-555-5555 from a French phone, you'd dial 001-555-555-5555. Easy! You may hear a brief message in French before it starts ringing; this is usually just to warn you that you're making an international call and the appropriate charges will apply.
Which calls are free? Which cost money?
It's often free to call a fixed line in France from another fixed line in France. So if you're staying in a rental apartment in Paris and using that phone to call, let's say, a restaurant, it'll probably be free. Just make sure the number you're calling starts with 01 or 09, meaning it's a fixed line.
Using a fixed line in France to call a cell phone in France (i.e. a number starting with 06) usually costs money.
Using a French cell phone to call any phone number will cost money, whether it's fixed line or another cell phone. There may be exceptions to this if you have a good cell phone plan that includes certain calls for free, but in general it'll cost ya.
When I first moved to France in 2005, I was surprised to see a majority of people, young and old, using text messages all the time, when the trend hadn't yet caught on in the US. I soon figured out why; for some reason, calling a French cell phone from another French cell phone can be very expensive (often starting at one Euro for the first minute and then getting cheaper for subsequent minutes), whereas sending a text message is usually much cheaper, like around 10 centimes (i.e. 0.10 Euros), or even free, depending on your plan. So sending a text message is always cheaper than making a call from a French cell phone.
Just for reference, the cheap pre-paid French cell phone service I used to use charged 10 centimes to send a text message to another French cell phone, and about 35 centimes to send a text message to a cell phone in the US. All of my calls started at at least one Euro, so texting is definitely cheaper every time.
Free calls home from fixed lines
If you're in someone's home, many French people have a fixed line in the house that can call other fixed lines for free, including phone numbers in the US and other countries! (The device/service I was most familiar with was called FreeBox, but there may be others.) Ask about this if you're renting an apartment for your stay, or if you're visiting someone's home! This can be extremely useful for keeping in touch with folks back home, or making plans to visit other countries in Europe during your trip.