BFM TV reported that a man armed with an automatic weapon walked into a flower shop at around 7.20am and began shooting.
Two employees were shot dead and a third man, believed to be the shop's owner, was shot in the knees.
The hooded attacker fled the scene.
Le Figaro named the two dead men as Stéphane Tixier and Amadéo Titeux and said both were known to the police and involved in organised crime.
All the men were aged between 40 and 50.
Police are studying closed circuit footage to see whether the attacker and an accomplice can be identified.