The shirt that started this thread is definitely not a German tropical shirt or French tropical shirt.
Judging by the use of the overlocker, I'm convinced that it is of post WW2 origin.
I've handled a few originals and currently have 3 Heer tropical shirts in the collection along with 2 French converted for German use and 2 unconverted French (for display under tunics).
I used to go to the various Militaria fairs in France and I remember that there were many WW2 French shirts for sale (they're "summer" shirts rather than tropical ones tough!) and I think that you could find one even now if you look for it hard enough...just remember that these shirts had a third button on the rear of the collar and small buttons made of brown glass.They're dark green in color and AFAIK they haven't been made after the War or,better,they have but there are a few differences and the WW2 have,more often than not,a round stamp inside with date and manufacturer.
IIRC I've seen the color photo of one of these shirts inside a book on the DAK,but cannot tell you which one!
Thank you very much for the info my friend