I have a Japanese book on Grothendieck's life and his mathematical works. The author writes that Grothendieck wrote manuscripts(over 250 pages) on "the category of manifolds" and "differential manifolds" for Bourbaki's famous textbook series. He writes that it was submitted in the Bourbaki congress in 1957, but it was rejected by the Bourbaki members for they thought it too algebraic.
Is this true? Does the manuscripts or the copy of it exist?