Answering my own question; T-Mobile confirmed that all three mobile
providers in France (Orange, SFR, Bouygues Telecom) are blocking
incoming SMS from T-Mobile USA. This is related to some contractual
disputes and it may not be resolved until some of the agreements with
those providers are renegotiated. The current workaround for this is
to use an email-to-sms gateway when available.
Cheers.
> Does anybody succesfully send SMS to a mobile in France? (particularly
> an Orange subscriber). If you do, how are you formatting the number?
> T-Mobile says that I should be able to do this and has opened a ticket
> to investigate why I can't, but so far nothing.
>
> Cheers.