thanks for the welcomes and the replies.
I came across the wrench on Sunday, in amongst a bunch of rusting items in a crate..... it was the fifth flea market (vide grenier) i had been to that day and I hadn't seen anything of interest up until then!
Interesting about the assembling of the Model T in Bordeaux, I am between Bordeaux and Toulouse, and also the Model A in Asnieres-sur-Seine (up around Paris). Wiki tells me they also assembled the Model Y (Ford 8 in France?), though dates suggest that would have been at Asnieres.
i have lots of Facom stuff gathered over the years, with the name either imprinted or embossed in a variety of ways, but have not seen the logo embossed like on this wrench, (almost like an acronym with the dots).
Facom developed as a hand tool manufacturer between the wars in the Paris region, mainly for the railway sector but expanding to other industries, so the Asnieres link seems good. (the history section on the official website is quite sparse for this time period).
Anyway, I woke up this morning and, as per usual, I learnt something new from this site!
Thanks all!