To my knowledge, only US crews operate the European and Far Eastern operations. We occasionally have a FedEx jumpseater and he flies from Memphis to either Japan or Paris to take the "local" runs.
A friend of mine in Europe looked into flying for Express, based out of Charles De Gualle (FedEx feeder) and apparently, the job hotline number he was given was the Memphis one! It appeared that you didn't have to be a US citizen or have right to work in USA in order to work for them. That's all I know.