Hollande's trip to the park in Stratford, east London, was long planned but came by chance the day after France triumphed in the men's 4x100m freestyle
relay and Camille Muffat won the women's 400m freestyle.
Hollande was welcomed to the Athletes' Village by French competitors including basketball star Tony Parker and Celine Goberville, who won a silver
medal in the women's 10m air pistol shooting.
The Socialist president had lunch with French athletes at the Village canteen and met the team's coaches and doctors.
Later he was expected to watch the women's handball clash between France and Spain, alongside British Prime Minister David Cameron.
France beat Great Britain 44-15 in a men's handball preliminary match on Sunday.
The home side scored first and kept in touch with France in the early stages before Britain's challenge fell away.
"Handball isn't our game," Cameron told BBC television.
"I'm not totally clear on all the rules -- perhaps President Hollande can give me a little tutorial as we watch it together."
Hollande was also set to watch swimming races at the Aquatics Centre.
The president is due to give a press conference at Club France – the French hospitality house in central London set up for the Olympics – before
dining with athletes from the French squad.
London beat Paris in the bid to host the 2012 Olympics.