This tumblr is good for french workwear flintstone (he also has an online shop)
Blue french work jackets are the classic, but I like the black ones too (black was worn by agricultural workers, blue by factory workers).
I also have a soft spot for vintage French fireman's uniforms (c. 1880s-1920s). They look a bit like military uniform but in indigo linen fabric.
There's a current season Dries jacket somewhat inspired by them (whole of Dries AW15 has some fireman's uniform influences with the buckled coats). Also the Visvim lugli which goes as far as to copy the collar embroidery. Actually a lot of recent Visvim pieces are French work wear inspired (travaill, bucky, lugli, pastoral pants, seabee, etc.)