Gallica is the digital library of the National Library of France and its partners, online since 1997. The page is available in French, English, German, Spanish, Italian and Russian. Today it offers access to several million documents. Among those documents there is a lot of interesting material for the dog pedigrees research. There is much more to find apart from the already posted Le Chenil, L’Eleveur and The Stud Book Continental.
For instance Le Sport universel illustré (1895-1936) and La Chasse illustrée (1867-1914) include a bunch of dogs’ photos, the latter admittedly mostly hunting dogs.
However, as it is impossible to leave through all those documents the best was is to enter a dog’s name in the “Advanced Search”, change the search pattern to “Text” and then go through the results.
Some results link to the web site Retronews, mostly advertisements, those ads sometimes have full info of a dog, including studbook number and parents. I usually enter the dog I search for to Gallica as well as Retronews.