I wrote about automobile streamlining in both the technical and stylistic senses here and here. Now I'd like to mention a body style introduced by Renault at the October 1934 Paris auto show that was a first tangible step in the streamlining direction, a step roughly in line with what a few American manufacturers were doing at the time. (I exclude the larger step made by Chrysler with its Airflow that was introduced for the 1934 model year.)
I said "tangible step" because effort was made to go beyond essentially cosmetic streamlining features such as fender skirts and slightly inclined radiator grilles such as appeared a year or two earlier; I'll explain in the photo captions below.
One side-detail I find interesting is the fact that Renault was able to afford to put these changes into production, given their total output in those days -- about 55-60,000 cars per year. And that production was divided amongst three different body/chassis types: the low-end "Quatre," the mid-high range "Stella," "Nerva" and "Viva" lines (variations on the same package) and the semi-streamlined "Grand Sport" shown below. I don't have enough data at hand, so my guess is that French cars, small and large, were relatively more expensive than American equivalents. Otherwise, how could Renault and other firms remain in business and keep up with the technological and styling theme times?
Let's look at the Renault Grand Sports that were designed in 1933 or thereabouts.