I noticed these two photographers while I was looking for background information on Brittany.
Georges Estève began working as a photographer in 1910 in the office of the Photographique des Beaux-Arts which became Des Archives photographiques in 1945. I noticed his photographs when researching the Churches in Brittany because they are elegant, and in black and white. His images can be found here. Sadly I cannot find any further information about him, not even his dates.
Mederic Mieusement (1840-1905) also specialised in architectural photography, starting in 1859. He too worked with the Government, the Beaux Arts Ministry, in recording buildings for renovation and preservation. His amazing photographs can be seen here.