Well, with these picture I have no doubt...the car is...a wrech! There are not many notices about this marque on the net; I understand that it began to build cars in 1913 using Malicet & Blin engines; after the first WW, Sigma built quite conventional cars both with CIME, SCAP and Ballot engines, from 800 to 1600 cc.
I have a pair of Sigma pictures in my archive, and the 20 cv is the one I think has some point in common with puzzle car, such as radiator and wheels. So that's my guess, Sigma 20cv tourer, 1925.