Mark in Paris[Purist]
10488
I saw a few in the 1937 to 1939 period
You can have a look at these references:
In 1937: in some 499, not all versions, even the 533 Chronograph (chronographs don't have often a swiss mention at all)
In 1938: in some 560, 565, 598, 556, the 591 Chronograph, 1420
In 1939: some 1435
Maybe the picture you're sharing shows it was displayed even later but it seems to be a very narrow period.
It seems to be explained by a French requirement that you can read about, here:
www.watchprosite.com
Best, Mark