SNCF Z 51500 51501Podensac Podensac

We have two identical pictures of Regiolis: this one and http://trainspo.com/photo/40249/
Here EMU is designated Z 50500, and there - Z 51500.
French Wiki says, that it is Z 50500. German Wiki states, that it is Z 51500.
"Z 51501" is slightly visible on the cab end of EMU.
So, where is the truth?

Yes there is an error in the French Wiki article, the EMU is Z 51500.

Cette rame est la responsable de faire des test, sans aménagements intérieurs.
Belle prise!