It had looked as though Spain were going to run away with victory at the Parc des Princes when they recovered from conceding an early goal to lead 3-1 by half-time.
Enzo Millot put France in front, but a Fermin Lopez brace and an Alex Baena free-kick turned the final completely on its head.
However, France staged a memorable comeback with Maghnes Akliouche pulling a goal back before Jean-Philippe Mateta converted a stoppage-time penalty awarded following a VAR review.
That took the final into extra time, where Rayo Vallecano forward Camello emerged as the hero by giving Spain the lead again in the 100th minute of an absorbing game, and then running away to seal their victory at the death.
“Coaches don’t go up onto the podium. That is for the players. They did this. They fought like a family,” Spain coach Santi Denia told radio station Cadena Cope.
“Luckily we have got the gold that Spain had been looking so hard for.”
Silver medallists in Tokyo three years ago, it is the second time Spain have won Olympic men’s football gold after their victory in Barcelona in 1992 with a squad featuring Pep Guardiola and Luis Enrique.
France had hoped for a second gold of their own, 40 years after winning in Los Angeles, but instead have to settle for silver.
“It didn’t finish the way we wanted it to but it was still really an extraordinary evening,” said Henry.
“It’s been a great run and we leave with a medal, so these will be great memories.”
