I've found a Mercedes that, to me, seems like the same model. Except I'm still not sure what model it is.
I'll give a point each to RtR and Allan L.
The original photo is out of the book "Three Men in a Motor Car" which details a trip taken from Paris to Algeria, to Tunisia, over to Sicilily, through Italy and then back to Paris. It's refered to as a Mercedes throughout the book, and it states that the car is an 18-24hp, even though I can't find a reference to an 18-24hp Mercedes in 1903.