Good job, Franck!
The photography shows the 1935 Imperia Sportwagen prototype during the Berlin car exhibition.
And as you´ve already said, it featured a three-cylinder, two stroke, RADIAL engine with 750ccm (ca.54 cui).
It is - as far as I know - the only car produced by Imperia, Bad Godesberg/Germany (not to be mixed up with the belgian company Imperia , located at Nessonvaux).
It would be great to have some more pics of it - does anybody have another view of it?