The flamboyant Frenchman, who had planned to end his career this year with a final bow at this week's Paris Masters, instead retired quietly last month amid the end of his marriage with fellow player Elina Svitolina.
Paris gave Monfils a send-off to remember, with fellow French favourites Jo-Wilfried Tsonga, Gilles Simon, Richard Gasquet and Benoit Paire joining him on court for a special ceremony.
"I'm not going to hide that, this is a very difficult moment to say goodbye," Monfils, 40, said in his farewell speech.
"The most beautiful thing that this world has given me is you, the wonderful crowd. It's not easy at all, but I'd really like to thank you all.
"Twenty-two years now that I've been a professional tennis player. Twenty-two years of an extraordinary story that I could have never dreamed of.
"I want to thank everyone, whether they're here or at home, because it's because of you that I could realise my dream."
The most personal moment came when Monfils addressed his daughter, reflecting on the game and the city that had shaped much of his life.
Monfils and Ukraine's Svitolina married in July 2021 and welcomed their daughter Skai in October the following year.
"Skai, your father was a tennis player," Monfils added.
"He loved tennis. He grew up in Paris, where he had a magnificent crowd behind him. I hope, from the bottom of my heart, that you will become a great champion in everything you do and that, one day, you will play here in Paris."
One of the most charismatic players of his generation, Monfils was renowned for his athleticism, flair and crowd-pleasing style.
He won 13 ATP Tour singles titles, lifting his first trophy in Poland in 2005 and his last in Auckland in January 2025.
Monfils' best Grand Slam results were semi-final appearances at the French Open in 2008 and US Open in 2016. His Grand Slam career ended at this year's US Open, where he was beaten by American Learner Tien in the second round.