The world over uses different GSM frequency bands, which prevents your GSM operated phones to be used in those countries. In France, the prevailing operational frequencies that are being used are - 900MHz and 1900MHz. France also uses the third generation mobile system called 3G system, not to be confused with GSM. Since, your GSM mobile phone would work on 1900MHz bandwidth it is just possible that your handset may work in France too. There are three types of handsets available today, which support multiple frequencies used in different countries. These are the dual band phones , Tri-band and the Quad-band. Dual band covers frequency bandwidths of 900 and 1800 MHz, which covers Europe, Asia, Australia and Brazil and 1900MHz covering North America. The European Tri-band handsets work on frequencies 900, 1800 and 1900 bands, providing good coverage in Europe and allowing limited use in North America. The North American Tri-band phones operate on 850, 1800 and 1900 for wide-spread North American service and have limited world-wide use. The Quad-band phones support all GSM frequencies and covers all the frequencies globally, including North America. Even if the phone you have works in France and you use your existing GSM phone in that country, you need to prepare yourself for certain things. First you will need to check with your service provider regarding activation of your GSM phone for roaming in France. If this can be done, you need to have it activated. But on the other hand this will prove to be very expensive, for, calls that you receive and make, will cost you more. There is an exorbitant per minute charge on top of, not only the calls you make but the calls you receive. The only way to avoid this is to buy a prepaid SIM card, specifically meant for France and you save up-to 80% of your call charges. There is no contract in this to be signed by you and there is no fear of receiving bills at the end of the month. On the other hand, if your phone is SIM unlocked, you may decide to buy a prepaid SIM card when you arrive in France. You can buy these SIM cards at phone shops in France and the major service providers are Orange, Bouygues Telecom and SFR.

Where-ever you are going it is worthwhile to check if your GSM phone is compatible with the frequency bands operating in the country of your visit. There is one more point to note. If you should need to rent a phone for your visit to France, or you decide to take your GSM phone and use a prepaid SIM card for France, make sure that your handset is SIM unlocked. Now what is a SIM unlocked mobile phone? When you sign a contract with a service provider, they would perhaps offer you a free mobile phone of your choice, within the range that they have, and in turn you would promise, through this contract, that you will be using their service for a definite period of time. During this time, the mobile phone which has come free to you is SIM locked. That would mean that you cannot use that phone with any other SIM card except the one given to you by your service provider. At the end of the contract, the service provider would help you to get that phone SIM unlocked. You need to be sure that in the event if you decide to take your GSM phone to France or rent one compatible phone, the handset is SIM unlocked so that you can use any SIM card what-so-ever, viz., the prepaid SIM card for France. You must not forget that your cell phone needs to be charged. You will need an adapter of the right kind to take along with you. In addition, the voltage output is different in France and your charger power plug will not fit into the kind of power plug that they have in France.