Count René Aldebert Pineton de Chambrun (French pronunciation: [ʁəne aldəbɛʁ pintɔ̃ də ʃɑ̃bʁœ̃]; 23 August 1906 – 19 May 2002) was a French-American aristocrat, lawyer, businessman and author.

He was the author of several books about World War II and his father-in-law, Vichy France Prime Minister Pierre Laval, to whom he served as legal counsel.

After Laval's sentence and execution in October 1945, Chambrun was put on police watch in Paris on the suspicion that he may have helped the Nazis during the war.

[14] For example, he wrote a letter to President Dwight Eisenhower in which he objected to his characterisation of Laval as "Hitler's most evil puppet" in his 1948 memoir entitled Crusade in Europe.

[15][16] Chambrun based his argument on another book, authored by Spanish Foreign Minister Ramón Serrano Suñer, in which the latter quoted Hitler describing Laval as "no better than De Gaulle.

[15][16] A decade later, in 1959, his wife wrote the foreword of Tout ce qu'on vous a cache, a book based on "German secret files" authored by Jacques Baraduc, Laval's lawyer.

[17] The book attempted to show that Laval "refused repeatedly to yield to German demands for a reduction in the number of United States agents in French North Africa and a limitation on their activity.

"[17] In 1969, Chambrun made an appearance in Marcel Ophüls's documentary on collaboration between the Vichy government and Nazi Germany during World War II, The Sorrow and the Pity (Le chagrin et la pitié).

[20] In 1970 Chambrun defended Greek shipping magnate Stavros Niarchos over false allegations that he killed his ex-wife, Eugenia Livanos.

[28] Upon Louis de Lasteyrie's death in 1955, Chambrun discovered the large cache of documents in the attic of the castle[29] and founded a private museum about Lafayette.

[30] News of his discovery brought many historians to his door, but Chambrun denied access, except to André Maurois whom he authorized to write a biography of Adrienne de Lafayette.

[33] There are now two major "Lafayette collections" in the world: one is at the Fondation de Chambrun; the other, originally assembled by Elie Fabius, at Cornell University Library.