The razor that I listed as a Hol'Pif came in a box with a Le Supreme label. So why do I have it listed as a Hol'Pif...
Follow my logic (and correct me if I'm wrong).

We are told that Hol'Pif went insolvent and was reborn as / or taken over by L'Essor and re-released the Hol'Pif razor as the Le Supreme.
I contacted someone on the forums that has a Hol'Pif and requested pictures and help.

The Hol'Pif that I have here has characteristics of both razors.
There are differences in the two but nobody has actually listed them, so here is my attempt to clear the murky waters.

In all the images below the first razor on the left is the mystery razor and the one on the right is the Hol'Pif. The one or sometimes two in the middle are both Le Supremes.

Starting right at the top:
The Le Supreme is a differential and the Hol'Pif's is not and because of this the Le Supreme has a notch in the topcap and base plate to indicate alignment.
The topcaps are also different shapes. The Le Supremes have squared off edges and the Hol'Pif has rounded edges.
The Mystery one has the squared edges but is not a differential so does not have alignment notches. 
I would hazard a guess here and say that the "differential" on a Le Supreme is as a result of the safety bars and not the topcap.

Moving down to under the topcap:
The Le Supremes have the posts on the underside of the topcap and the Hol'Pif have them on the base plate. The Mystery has them on the topcap, but there is a slight difference - the pins are chamfered and a bit flattened. The ones on the Le Supreme are more rounded.

Then on to the top of the base plate:
The base plate has round holes vs the oblong holes of the Le Supreme. The pins of the Hol'Pif are on the base plate but have the centres drilled out.

Moving down to under the base plate.
The Le Supreme is branded with "LE SUPREME" on one side and "RASOIR REGLABLE / B te S.G.D.G. on the other. The Hol'Pif has no branding.
The Mystery is like a Hol'Pif and has none.

The adjuster dial:
The knurling on a Le Supreme is coarser than a Hol'Pif and the font is also slightly different.
Mine has the finer knurlinfg and also the Hol'Pif font.

Lets go to the handle.
At first glance the handle could be either. I have a Le Supreme with the same knurling however there is a slight difference - the handle on the Hol'Pifs are 1mm thicker. Mine is the latter.

We now move onto the Twist-knob,
It has the groove in the middle like a Le Supreme but the fine knurling of a Hol'Pif.
The underneath is not hollowed out, so also like a Hol'Pif, but its more chamfered.

And then Last but not least:
Hol'Pif's the handles are also removable while Le Supremes are not.

Everything except the pins under the topcap and the case it arrived in indicate Le Supreme but pretty much everything else says Hol'Pif.
The twist knob seems to be a hybrid of the two.

Best guess at the moment is that its some sort of transition model where Le Supreme used up some of the old stock that they took over and made razors to sell.

Most of the differences indicate a Hol'Pif, so now you know why I have it listed as a Hol'Pif rather than a Le Supreme