The Argentine speedster took the win after a sprint finish in the race that is part of the Coupe de France series.
Alex Rasmussen (Garmin-Barracuda) finished second in the race with Andrea Guardini (Farnese Vini) third.
Haedo avoided a pile-up with 10km to go to record his first victory since stage 16 of last year's Vuelta a Espana.
His team worked hard to reel in two escapees.
"I've seen JJ getting stronger and stronger and I knew it was only a matter of a short period of time before he made it," said Saxo Bank sports director Fabrizio Guidi after the race.