Denis said Ms Bruni had offered to put him up in a hotel
It is a heart-warming tale of rags and riches - or first lady and the tramp.
Carla Bruni has reportedly befriended a homeless man who lives near her home in Paris's 16th arrondissement, giving him money and talking about music.
The wife of French President Nicolas Sarkozy had even offered to put Denis up in a hotel, he told Closer magazine.
He said the two had struck up conversation as the Italian-born model and singer, 41, passed Denis on the daily school run with her son.
"She asks after me, she gives me one or two 50- or 100-euro notes," Denis, 53, was quoted as saying by the UK's Daily Telegraph newspaper.
He added that the two discussed books or music, and the first lady had even given him a signed copy of her latest album.
But Denis turned down Ms Bruni's offer to put him up in a hotel room for a month.
"It's not that I enjoy being in the street but I've got my habits," he was quoted as saying. "People say it's cold. That's true but I'm well covered-up.
"What's more, Carla gave me a military-type duvet, which keeps me warm."
Denis was interviewed by Closer after Ms Bruni mentioned their conversations in an interview with Macadam, a magazine sold by the homeless.
Ms Bruni married twice-divorced French President Nicolas Sarkozy in 2008 after a whirlwind romance.