6 May 1925, Parc des Princes Concours d'Elegance
Entry #95
4th Place, Amateur Category
1925 Panhard of J. Dupont-Combes
Bunau-Varilla Patented Transformable Coachwork by Carrosserie Figoni (under licence)
My original (reliable, period) source identified the coachbuilder as "Carrosserie Bunau-Varilla." However, I was able to find another (also reliable, period) source which identified Figoni as the coachbuilder. During this period in time, Figoni--the more prolific coachbuilder of the two--bodied several cars using methods patented by Bunau-Varilla (under license, of course). I think this was likely the case with the puzzle car as well. One of the body tags shown below possibly reads:
SOUS LICENCE
BUNAU-VARILLA
Unless somebody has evidence to the contrary, I am calling this one "solved" and awarding the point to FrontMan.
Better photo and details: