A point to Joćo for finding the owner and Panhard connection. A point to Wendax for digging out the actual name of the vehicle, "La Bourlinguette".
I'm surprised so much information about this vehicle was found in German. La Bourlinguette was also described, in English, in the Motor-Car Journal from October 10th, 1903.
Strangely enough, this apparently newer, green vehicle also carries the name La Bourlinguette. It is described as being constructed by Henri Lafitte in Bordeaux. The name, boxy design, and solid wheels are similar. I am inclined to believe, the Henri Lafitte descriptive text refers to M. Secrestat's original vehicle.
(January 2022 revision: A French magazine article describes this green vehicle as a 1913 Loiret, based on a Renault chassis. The image label indicating this is La Bourlinguette is incorrect.)