I am not sure any of the above replies are right.
FAR 61.3 allows an N-reg to be flown (outside the USA) on any foreign license so long as the license is issued ("validated" is not good enough) by the country owning the airspace.
So, you can fly an N-reg in France on a French issued license, in Germany on a German issued license, etc.
Some people believe that a JAR license is good for all of JAR-land. I have two replies from the FAA which directly contradict each other on this matter. So this is a grey area. But a strict reading of 61.3 (which anybody who can read can do) says this is wrong because the word it uses is issued.
I don't see what difference having a CPL (as opposed to a PPL) makes to the above - it merely enables you to act as a paid pilot flying your employer around in his plane.