How to call from Paris to another country

Dial the international code 00, the code of the country, then the number without the first 0.

With the France Télécom Pays Direct service, you can obtain an operator in your own country free of charge. If you wish, he can establish reverse-charge calls for you (where the person called pays for the communication).
For this service, dial 0 800 99 00 + country code.

Examples:
34 for Spain
49 for Germany
44 for UK
39 for Italy
11 (AT&T) or 19 (MCII) for US
16 for Canada (0 800 99 30 16 AT&T Canada)