I searched myself to see the specs of a nokia n900 FR and an US


US = Operating Frequency
Optimized for WCDMA 900/1700/2100
Quad-band EGSM 850/900/1800/1900
Optimized for 3G networks on WCDMA 900/1700/2100 Quad-band EGSM 850/900/1800/1900

FR = Fréquence de fonctionnement
Quad-band EGSM 850/900/1800/1900, WCDMA 900/1700/2100
Commutation automatique entre bandes GSM
Mode Avion


It's approximately the same. By deduction, the US nokia will work in France.

But i hope a confirmation