AlexFrance has contacted me by PM with a link to the SCAP specialist and his comments. It is interesting reading. Basically no such car as this was ever built by SCAP - it appears to be, as Alex says, a SCAP Type Y engine fitted onto what could well be a La Perle chassis, which in turn had been supplied to them by Malicet et Blin. No way was it built in 1919 - SCAP didn't start making cars again until 1920, with the Type L.
My guess is that this car is what we call in the UK a "bitsa" - bits of one car, and bits of another. It's powered by SCAP, because the motor has the maker's plate, and the radiator suggests that make as well, but the model wasn't ever made. It has been called a Type Y because it has a Type Y engine.
My apologies for setting a puzzle I hadn't researched properly. I have amended the puzzle title accordingly. And well done to AlexFrance for an excellent piece of detective work!