About your Duvert Freres, the first registration of trademark for this firm was in 1887, from Thiers France.
Their last registration was in 1920, im sure its a fine shaver! Enjoy!
Thanks again!
The #69 and the one restored #19 I have are both very nice shavers, I'd give the edge, in my preference, to the #69...guess I'll send the Le Grelot and the other #19 for a cleaning and honing...release them from storage.