He was at times both Saint Laurent’s right-hand man and his partner, helping him to become Christian Dior’s successor in France’s haute couture.
Berge and Saint Laurent were joined in a civil union a few days before the designer died of a brain tumour in 2008.
Earlier this year, he was credited with helping French president Emmanuel Macron in office, with Town And Country Magazine calling him one of the “most powerful men in France”.
His political engagement made him Grand Patron of Arts and Culture in 2001, overseeing paintings purchase at the Louvre and the renovation of two rooms at London’s National Gallery.
“He was a magician who made his life and those who he loved a symphony of happiness,” former French culture minister Jack Lang said.
“Pierre Berge was above all a marvellous and loyal friend… who was there to take on all the good fights, the noble causes, in particular to provide the means for research to defeat AIDS.”
During his life and career, Berge was considered a confidant of powerful men such as former French president Francois Mitterrand, Jean Cocteau and Albert Camus.