Rochefoucauld was one of the first to popularize the use of the 'maxim' and influenced the style of many philosophical writers including Nietzsche.
The book can be found here:François VI, duc de La Rochefoucauld, also called (until 1650) Prince de Marcillac, (born September 15, 1613, Paris, France—died March 16/17, 1680, Paris), French classical author who had been one of the most active rebels of the Fronde before he became the leading exponent of the maxime, a French literary form of epigram that expresses a harsh or paradoxical truth with brevity. (https://www.britannica.com/biography/Francois-VI-duke-de-La-Rochefoucauld)
https://www.gutenberg.org/ebooks/9105
I would also suggest his book 'Memiors' but I can't find it on Gutenberg.