Some info on here http://en.wikipedia.org/wiki/Nissan_VQ_engine
Seems as though the DE engines were made in the US and Japan, it would be assumed that they shipped the motors to France for fitting in the Espace, Vel Sartis and Espace... I think the case that there would be some small differences due to the difference in HP, but that could be down to the maps on the ECU's as these will be changed to meet different countries fuel, environmental constraints etc...
There was lots of talk about the whole renault / nissan thing and who did what for the cars... Am sure that some people that have been around the cars for sometime wil be able to shed some light!