Here is a link to purchase a sample of toe rail. It's manufactured by Osculati, so may well have been used by Dufour. https://www.beachyheadmarine.com/toe-rail-and-fitting-c102x3048924
I googled "rail de fargue pour voilier dufour" and got these results which you can mine for more exact info:
https://www.google.com/search?q=rail+de+fargue+pour+voilier+dufour&rlz=1C1CAFA_enIE653IE680&sxsrf=ALiCzsZlqinG6uTpYw4uiSFTq_NFtjBsag%3A1665659551757&ei=n_JHY9vlLc-ZgQbM4pqgCg&ved=0ahUKEwibsZivid36AhXPTMAKHUyxBqQQ4dUDCA4&oq=rail+de+fargue+pour+voilier+dufour&gs_lcp=Cgxnd3Mtd2l6LXNlcnAQDDoKCAAQRxDWBBCwA0oECEEYAEoECEYYAFC0CFiZJWDjRGgBcAF4AIABc4gB9wWSAQM1LjOYAQCgAQHIAQjAAQE&sclient=gws-wiz-serp
Googling "un echantillon (a sample) de rail de fargue" did not produce any better results
You can click on "Translate this page" if French is not your forte
I would surmise that it is Goiot.