Hello Denny!
I`m also very interested in this time and place, a fascinating and exciting topic.
As already mentioned, there are lots of books in french by "guide de chasse" many are still available by the french publishing house "Montbel".
I recommend the following books in english about hunting in French Equatorial Africa, they have lots of interesting facts (although some of them deal in parts with the period before or after the 1950s):
Christian Le Noel:
"On Target - History and Hunting in Central Africa" (Best source on hunting in the french colonies, one of my favourite books, great historical hunting photos).
Gilles Tre-Hardy:
"The Path of a Hunter" - The author was a Game Warden and Professional Hunter in Oubangui Shari / CAR from the 1950s on. Great reading and stunning pictures of huge elephants).
Robert Montvoisin:
"Professional Hunter" - Memoirs of a french hunting guide from the end of the 1940s up to the 1990s! Much about hunting in the french colonies.
Francois Sommer:
"Man and Beast in Africa" - Foreword by Ernest Hemingway (!), mainly about big game in the french colonies, but also East Africa.
Hans-Otto Meissner:
"One-Man Safari" - Several self-organized hunts in Oubangui Shari, Gabon, Tchad, Congo, etc. early 1950s.
Ernst A. Zwilling:
"Jungle Fever" - Memoirs of an Austrian PH in Cameroon, Central Africa and Tchad.
Albert Mahuzier:
"Tragic Safari" - Photography and hunting in Tchad and Oubangui; the author's french hunting guide is killed by a lion...
Giorgio Grasselli:
African Sunsets - Book by an Italian PH, much on CAR, also Cameroon and Zambia.
Sache de Montbel:
"Big Game Hunting" - Worldwide hunts, but also some chapters about Central Africa and Congo in the 1950s.
I also recommend the books by
Frank Hibben ("Hunting in Africa" or "Under the African Sun") and
Warren Page ("One Man's Wilderness"). Both writers hunted in French Equatorial Africa in the 1950s for Bongo, Giant Eland and other game. But there are chapters about other countries as well.
Check out Tony Sanchez-Arino (he started hunting in 1952 in Guinea and French Equatorial Africa). The best books for your purpose are
"From the Congo River to the White Nile",
"Claws and Fangs",
"The Last of the Few", "Elephant Hunters, Men of Legend". He is now 94 years old, but maybe you could contact him and ask some questions.
All the other material i have about hunting in French Equatorial Africa is either in the wrong timeframe or in the wrong language.
Good luck for your research and best wishes!